Learn Hardcore Croatian: Sutra ću se prijaviti na natječaj, jer ponuda izgleda pošteno. - Tomorrow I will apply for the competition, because the offer looks fair.

Ću is the future tense auxiliary; it comes from the verb htjeti (to want), but in modern Croatian it mostly functions as a future marker, not as “I want” in this context.

ću = I will
Sutra ću se prijaviti = Tomorrow I will apply

So the real lexical verb is prijaviti (se), and ću just builds the future tense.

Why is the word order ću se prijaviti and not se ću prijaviti?

Both ću and se are clitics (very short, unstressed words) and Croatian has quite strict rules about their order:

Clitics usually go in second position in the clause (after the first stressed word or phrase). Here, the first stressed word is Sutra, so the clitics follow it:
- Sutra ću se prijaviti…
Within the clitic group, the order is fixed. The auxiliary ću must come before the reflexive pronoun se:
- correct: Sutra ću se prijaviti
- incorrect: Sutra se ću prijaviti

So “se ću” is simply not allowed in standard Croatian.

Why do we need se with prijaviti? What does prijaviti se mean exactly?

The verb prijaviti can be:

non‑reflexive: prijaviti nekoga = to report / register someone
reflexive: prijaviti se = to apply / sign up oneself

In this sentence, prijaviti se (na natječaj) means “to apply (oneself) for a competition / job ad / tender”, so se is required to show that the subject = the person being applied.

Compare:

Prijavit ću se na natječaj. – I will apply (myself) for the competition.
Prijavit ću ga na natječaj. – I will enter him for the competition. (different person)

Without se, the meaning changes or sounds incomplete.

Why is it na natječaj and not something like za natječaj? Which case is that?

Na natječaj uses:

the preposition na +
accusative case (natječaj, same form as nominative here)

For “apply for sth”, Croatian typically uses:

prijaviti se na natječaj / na fakultet / na tečaj
(apply for a competition / to a university / to a course)

Using za here (prijaviti se za natječaj) is non‑standard or at least unusual; native speakers strongly prefer na with prijaviti se in this meaning. The preposition is mostly a matter of collocation (fixed pairing of verb + preposition).

What exactly does natječaj mean? Is it only “competition”?

Natječaj is broader than just “competition.” It’s often:

a call for applications,
a tender,
an official announcement that you can apply for some position, funding, scholarship, contract, etc.

Examples:

natječaj za posao – job ad / job competition
natječaj za stipendije – scholarship call
javni natječaj – public tender

So prijaviti se na natječaj usually implies submitting an application in some formal process, often related to jobs, grants, contracts, etc.

Why is there a comma before jer? Is it obligatory?

Yes, in standard Croatian a comma before “jer” is normally obligatory, because:

jer introduces a subordinate clause of reason (a “because”-clause).
Such clauses must be separated from the main clause by a comma.

So:

Sutra ću se prijaviti na natječaj, jer ponuda izgleda pošteno.
Main clause: Sutra ću se prijaviti na natječaj
Subordinate clause: jer ponuda izgleda pošteno

In everyday writing, some people omit the comma, but in correct written Croatian you should keep it.

What’s the difference between jer and zato što? Could I say … zato što ponuda izgleda pošteno instead?

You can say that, but there’s a nuance:

jer = “because”; neutral, very common in both spoken and written language.
zato što = literally “for that (reason) that…”; often slightly more explicit / emphatic and sometimes feels a bit more formal or logical (“for the reason that…”).

Your sentence with zato što:

Sutra ću se prijaviti na natječaj, zato što ponuda izgleda pošteno.

is grammatically fine and understandable. Many speakers would still prefer jer here, because it’s shorter and more natural in casual speech.

Why is it pošteno and not poštena ponuda izgleda? What’s going on with the ending -o?

Pošteno here is an adverb meaning “fairly / in a fair way”.

pošten – fair, honest (adjective, masculine)
poštena ponuda – a fair offer (adjective + noun)
izgleda pošteno – it looks fair / it appears fair (adverb)

In English you say “the offer looks fair” (adjective), but in Croatian with verbs like izgledati (to look/appear) it’s very common to use an adverb in -o:

ponuda izgleda pošteno – the offer appears fair
to zvuči čudno – that sounds strange
ponaša se pristojno – he/she behaves politely

You could also say ponuda je poštena (the offer is fair), but that slightly changes the structure (using je instead of izgleda) and feels more like a direct statement than a perception.

Can I move sutra to a different place? For example: Prijavit ću se sutra na natječaj?

Yes, sutra (tomorrow) is flexible in word order. Some natural variants:

Sutra ću se prijaviti na natječaj.
Prijavit ću se sutra na natječaj.
Prijavit ću se na natječaj sutra. (a bit less common, but possible)

What you must keep is:

the correct order of clitics: ću se, never se ću
overall word order should remain clear and not overly scrambled.

So:

Prijavit ću se sutra na natječaj. – OK
Sutra ću se prijaviti na natječaj. – very natural
Na natječaj ću se sutra prijaviti. – possible, but sounds like you are emphasizing “for that competition” in a more marked way.

Why is it prijaviti here, but sometimes I see prijavljivati? What’s the difference?

This is about aspect:

prijaviti (se) – perfective: a single, completed action of applying
prijavljivati (se) – imperfective: a repeated / ongoing / habitual action of applying

In the future tense for a one‑time action, you normally use the perfective:

Sutra ću se prijaviti na natječaj.
Tomorrow I will apply (once).

If you talk about something happening regularly or over time, you’d use the imperfective:

Često se prijavljujem na natječaje.
I often apply for competitions.
Već se mjesecima prijavljujem na razne natječaje.
I’ve been applying to various calls for months.

So here, prijaviti se is the right choice because it’s a single, planned future action.

Why is it Sutra ću se prijaviti and not a present tense like Sutra se prijavljujem?

Both are possible, but they have different nuances:

Sutra ću se prijaviti – straightforward future tense; neutral, standard way to talk about a future action.
Sutra se prijavljujem – present tense used with a future time adverb (“tomorrow I’m applying”).
This can sound:
- more colloquial, and
- often implies a firm plan / arrangement, similar to English “I’m applying tomorrow” (present continuous with future meaning).

In formal or neutral written Croatian, future I with ću is usually preferred:
Sutra ću se prijaviti na natječaj.

Is there a difference between Sutra ću se prijaviti na natječaj and Sutra ću se prijavit na natječaj?

Yes, this is an orthographic / stylistic issue tied to future tense formation.

Rules in standard Croatian:

When the auxiliary ću comes after the verb, you usually drop the final -i:
- Prijavit ću se. (not Prijaviti ću se in standard spelling)
When ću comes before the verb (as in your sentence), you keep the full infinitive with -i:
- Sutra ću se prijaviti na natječaj.

So, in standard written Croatian it should be:

Sutra ću se prijaviti na natječaj. (correct)
Sutra ću se prijavit na natječaj. – colloquial spelling; common in speech/transcription, but non‑standard.

Is the sentence formal, informal, or neutral in style?

The sentence is neutral; it works in both everyday and relatively formal contexts.

Vocabulary like prijaviti se na natječaj, ponuda, pošteno is standard and not slangy.
The structure with jer and a full sentence after it is also neutral.

You could easily use this in an email, a conversation with friends, or in moderately formal speech without sounding out of place.

Could I drop jer and just say Sutra ću se prijaviti na natječaj; ponuda izgleda pošteno?

You can, but the relationship between the two clauses changes:

With jer:
Sutra ću se prijaviti na natječaj, jer ponuda izgleda pošteno.
= I will apply because the offer looks fair.
(explicit cause‑and‑effect)
Without jer:
Sutra ću se prijaviti na natječaj; ponuda izgleda pošteno.
= I will apply for the competition; the offer looks fair.
(two statements placed side by side; the reader can infer the causal link, but it is not grammatically marked)

So it’s grammatical to omit jer, but you lose the explicit “because” meaning.