Learn Hardcore Norwegian: Til slutt sier psykologen at slik ærlig oppførsel overfor hverandre er både sunn og fornuftig. - In the end the psychologist says that such honest behavior toward each other is both healthy and sensible.

Til slutt sier psykologen at ... (as in the original) – neutral, very common.
Psykologen sier til slutt at ... – slightly more focus on when the psychologist says it.
Psykologen sier at ... til slutt. – puts extra emphasis on the timing; often used in speech for contrast.

All three are grammatical. Moving til slutt mainly changes emphasis, not the core meaning.

Why is the word order Til slutt sier psykologen ... and not Til slutt psykologen sier ...?

Norwegian main clauses follow the V2 rule (verb-second):

One element in the first position (here the adverbial Til slutt).
The finite verb in second position (here sier).
The subject and the rest after that (here psykologen ...).

So:

First position: Til slutt
Second position (must be the verb): sier
Then subject: psykologen

Til slutt psykologen sier ... would break the V2 rule and is ungrammatical in standard Norwegian.

Why is it psykologen (the psychologist) and not en psykolog (a psychologist)?

Norwegian uses the definite suffix (here -en) to express the:

psykolog = psychologist (bare noun, or used in compounds)
en psykolog = a psychologist
psykologen = the psychologist

In this sentence, psykologen implies:

either a specific psychologist already known from the context, or
a particular role in the situation (for instance, “the psychologist in this case / in this story”).

If you said en psykolog, it would sound like you are introducing some random, new psychologist, not one already established in the context.

What exactly is slik doing here, and how is it different from så or sånn?

Here, slik is a determiner meaning such / this kind of / that sort of:

slik ærlig oppførsel = such honest behaviour / behaviour like that

Differences:

slik – neutral/standard, often used in writing.
sånn – very common in speech, more informal; often interchangeable with slik in everyday conversation:
- sånn ærlig oppførsel = slik ærlig oppførsel in informal style.
så – means so / so very (degree), not such:
- så ærlig oppførsel would mean so honest behaviour (unusual phrasing).

So here slik points back to a type of behaviour that has been described or is understood from the context.

Why is the adjective order slik ærlig oppførsel and not ærlig slik oppførsel?

In Norwegian, the normal order inside a noun phrase is:

[determiner] + [adjectives] + [noun]

Here:

slik = determiner (such)
ærlig = descriptive adjective (honest)
oppførsel = noun (behaviour)

So the natural order is:

slik ærlig oppførsel

Ærlig slik oppførsel is not natural Norwegian; it sounds like you are trying to say something like honest such behaviour, which does not work idiomatically.

What does oppførsel mean, and is it countable? What gender does it have?

Oppførsel means behaviour / conduct.

About its grammar:

It is usually uncountable (like English behaviour):
- god oppførsel = good behaviour
- You very rarely (essentially never) see a plural oppførsler in normal language.
Gender: in Bokmål it is usually treated as common gender:
- en oppførsel (or less often ei oppførsel)
- oppførselen = the behaviour

In practice, you mostly see it in indefinite singular or definite singular:

slik oppførsel (such behaviour)
oppførselen hans er dårlig (his behaviour is bad)

What does overfor mean here, and how is it different from ovenfor or mot?

In this sentence, overfor means towards / in relation to:

ærlig oppførsel overfor hverandre
= honest behaviour towards each other / in relation to each other

Important distinctions:

overfor (one word)
- abstract or relational: overfor noen = in relation to someone, towards someone (not physically)
- also can mean opposite / facing in spatial sense (e.g. sitting across from someone), but here it is relational, not spatial.
ovenfor
- purely spatial: above / higher up (e.g. leiligheten ovenfor = the apartment above).
mot
- more general towards / against.
- ærlig mot hverandre is understandable, but overfor is more idiomatic when you mean in your conduct/attitude towards each other.

So overfor hverandre here is best read as towards each other (in how they behave).

What does hverandre mean, and when can it be used?

Hverandre is a reciprocal pronoun meaning each other / one another.

Usage rules:

It refers to at least two people or things:
- De liker hverandre. = They like each other.
It is typically the object of a verb or preposition:
- snakke med hverandre = talk with each other
- overfor hverandre = towards each other
It cannot be used with a singular subject:
- You cannot say han liker hverandre.
It cannot be the subject:
- You cannot say hverandre er snille; you must say de er snille mot hverandre (they are kind to each other).

In this sentence, hverandre is the object of overfor: behaviour towards each other.

What does både ... og express in er både sunn og fornuftig?

Både ... og means both ... and. It is used to emphasize that two (or more) things are true at the same time.

Here:

både sunn og fornuftig = both healthy and sensible

Without både, you could say er sunn og fornuftig (is healthy and sensible). That is still correct, but både ... og adds a small emphasis that both qualities apply, not just one.

Why are the adjectives sunn and fornuftig in this form? Why not sunne, fornuftige, or with -t?

In the phrase:

slik ærlig oppførsel overfor hverandre er både sunn og fornuftig

the subject of the verb er is slik ærlig oppførsel overfor hverandre. The core noun oppførsel is singular and common gender.

Adjectives in predicative position (after er, blir, etc.) agree with the noun:

Common-gender singular: sunn, fornuftig
Neuter singular: sunt, fornuftig (no extra ending)
Plural / definite: sunn(e) → sunne, fornuftige

So:

oppførsel(en) er sunn og fornuftig is correct.
oppførsel(en) er sunne or fornuftige would wrongly suggest a plural subject.
oppførsel(en) er sunt would be wrong gender (neuter).

In the part at slik ærlig oppførsel overfor hverandre er ..., why doesn’t the verb come immediately after at? Isn’t Norwegian verb-second?

The V2 rule (verb-second) applies only to main clauses.
In subordinate clauses (clauses introduced by at, som, fordi, etc.), the basic order is:

[subordinating conjunction] + [subject] + [adverbs] + [verb] + ...

So here:

at = subordinating conjunction
slik ærlig oppførsel overfor hverandre = subject
er = verb

Order:

at
- slik ærlig oppførsel overfor hverandre
  - er
    - både sunn og fornuftig

Putting the verb immediately after at (at er slik ærlig oppførsel ...) would be ungrammatical.

Could I say Til slutt så sier psykologen at ...? I often hear så after something at the start.

Yes, Til slutt så sier psykologen at ... is very common in spoken Norwegian and in informal writing.

What is going on:

så here is a kind of linking word / discourse marker, not the main verb.
The true finite verb sier is still in second position among the real sentence elements.

However:

In formal written Norwegian (essays, reports, etc.), you usually leave out this extra så:
- Til slutt sier psykologen at ... is the recommended form.
In everyday speech, many people would naturally say Til slutt så sier han ...

Can I move til slutt and say Psykologen sier til slutt at ...? Does that change the meaning?

Yes, you can say:

Psykologen sier til slutt at slik ærlig oppførsel ...

This is perfectly grammatical.

Meaning:

The core meaning (the psychologist eventually says that...) is the same.
Word order in Norwegian is quite flexible for adverbials like til slutt, and moving it mainly affects emphasis and rhythm, not what is actually being asserted.

Compare:

Til slutt sier psykologen at ...
– foregrounds the time or sequence of events.
Psykologen sier til slutt at ...
– foregrounds the psychologist as the topic, with timing as extra information.

What is the role of at in this sentence, and could it be replaced by something else?

At is a subordinating conjunction meaning that. It introduces a content clause that functions as the object of sier:

Main clause: Til slutt sier psykologen
Object clause: at slik ærlig oppførsel overfor hverandre er både sunn og fornuftig

So the structure is like:

He says that [clause].

You cannot replace at with som here:

som is mainly a relative pronoun (who/which/that) or a comparative marker, not a that introducing a whole statement.

In everyday Norwegian, at is sometimes left out when the clause is short and informal, but here it would sound odd or too casual to omit it. The standard written form keeps at.

Why is there no comma before at in this sentence? I thought Norwegian usually uses a comma before subordinate clauses.

Older comma rules in Norwegian almost always required a comma before subordinate clauses, including at-clauses.

Modern practice (and official recommendations) allow:

No comma before an object clause introduced by at when it directly follows the verb:
- Til slutt sier psykologen at slik ærlig oppførsel ... ✅
A comma is possible in some styles, but often looks old-fashioned or heavy:
- Til slutt sier psykologen, at slik ærlig oppførsel ... – possible, but not typical in contemporary style.

So the version without a comma in your sentence is modern and standard.