Learn Hardcore Swedish: Hon känner sig trygg hemma.

So without sig, känner does not mean feels (emotion/state). You need sig to mean feels herself in an emotional/mental/physical state.

What exactly does sig mean here? Is it like herself in English?

Yes, sig is a reflexive pronoun, and it corresponds roughly to himself / herself / itself / themselves in English.

Hon känner sig trygg. = She feels herself safe → She feels safe.
Han skadar sig. = He hurts himself.
De tvättar sig. = They wash themselves.

In this sentence, sig doesn’t add extra emphasis like English herself sometimes does; it is simply required by the verb känna sig to create the meaning to feel (a certain way).

Could I say Hon är trygg hemma instead? What is the difference between känner sig and är?

Both are possible, but there is a nuance:

Hon känner sig trygg hemma.
Focus: her subjective feeling. She experiences safety at home.
Hon är trygg hemma.
Focus: her state or situation is safe at home; it sounds a bit more objective or descriptive.

In many everyday contexts they can overlap and both sound natural, but:

If you’re talking about how she experiences it (emotionally), känner sig is more typical.
If you’re stating a fact about the situation (home as a safe environment), är trygg fits well.

Still, Swedish speakers might use either, depending on what they want to emphasise.

Why is it trygg and not tryggt or trygga here?

Trygg is an adjective. In Swedish, when an adjective comes after a verb like är or känna sig, it agrees in number (singular/plural) and definiteness, but not in grammatical gender in this position.

For a single person (like hon):

Hon är trygg.
Hon känner sig trygg.

For several people:

De är trygga.
De känner sig trygga.

You only use -t (like tryggt) when the adjective describes an ett-word noun directly:

Ett tryggt hem. = A safe home.
Ett tryggt område. = A safe area.

Here, trygg is not describing a noun; it is describing hon via känner sig, so it stays trygg.

What is the difference between trygg and säker? Don’t they both mean safe?

Both can be translated as safe, but they are used differently:

Trygg

Often about emotional security and feeling protected.
Common with people and atmospheres:
- Hon känner sig trygg hemma. = She feels safe/secure at home.
- Det är en trygg miljö. = It is a secure environment (emotionally, socially, etc.).

Säker

Often about objective safety or certainty.
- Det är en säker bil. = It is a safe car (technically safe).
- Jag är säker. = I am sure/certain.

If you say Hon känner sig säker hemma, it can still mean she feels safe, but it may also be interpreted as she feels sure/confident at home. Trygg is the most natural choice for the emotional sense of feeling safe.

Why is it hemma and not hem or i hemmet?

These three are related but used in different ways:

hemma = at home (location)
- Hon är hemma. = She is at home.
- Hon känner sig trygg hemma. = She feels safe at home.
hem = (to) home (direction / movement)
- Hon går hem. = She is going home.
- Hon vill hem. = She wants to go home.
hemmet = the home / the house (as a noun)
- Hemmet är litet. = The home is small.
- Hon känner sig trygg i hemmet. = She feels safe in the home (more formal / specific).

In your sentence it’s about being at home, so hemma is the natural choice.

Can I say Hon känner trygg hemma without sig?

No, that is not correct Swedish.

To express how someone feels (emotionally or physically) with an adjective, you must use känna sig:

✅ Hon känner sig trygg hemma.
❌ Hon känner trygg hemma.

Without sig, känna needs an object or has another meaning (to feel/touch, to know), and the sentence becomes ungrammatical.

Where would the negation go if I want to say She does not feel safe at home?

You insert inte (not) after the verb känner and before sig:

Hon känner inte sig trygg hemma. ❌ (sounds wrong)
Hon känner sig inte trygg hemma. ✅

Correct sentence:

Hon känner sig inte trygg hemma.
= She does not feel safe at home.

With känna sig, the normal pattern is:

[subject] + känner + sig + inte + [adjective] …

Why is it Hon and not Henne at the start of the sentence?

Hon is the subject form (like English she).
Henne is the object form (like English her).

Hon känner sig trygg hemma.
She feels safe at home.
→ Hon does the action, so subject form.
Jag ser henne.
I see her.
→ Henne receives the action, so object form.

At the beginning of your sentence, the word is the subject, so it must be Hon.

Could I also say Hon känner sig trygg hemma hos sig? What is the difference?

Yes, you can say:

Hon känner sig trygg hemma hos sig.

Nuance:

hemma already means at home, and in many contexts that is enough and sounds most natural.
hemma hos sig literally is at home at her own place, and it very clearly emphasizes that it is her own home, not someone else’s.

Use hemma hos sig if you want to contrast it with other places where she does not feel safe, or if you want to stress her own home specifically.
In neutral sentences, hemma alone is usually fine.

What tense is känner here, and does it mean right now or in general?

Känner is the present tense of känna.

Swedish present tense can cover both:

Right now:
Hon känner sig trygg hemma (just nu).
She feels safe at home (right now).
In general / habitually:
Hon känner sig alltid trygg hemma.
She always feels safe at home.

Context or adverbs (like alltid, ofta, just nu) tell you which meaning is intended.

How is känner pronounced, and is the k sound hard or soft here?

Känner is pronounced roughly like "shen-ner" in English approximation.

The k before ä becomes a soft sound, similar to English sh.
ä is like the vowel in English bed, but a bit more open.

So:

känner ≈ "shen-ner"
känna ≈ "shen-na"

This soft k before e, i, y, ä, ö is a common pattern in Swedish.