Sutra ćemo se pobrinuti za prigovor.

Croatian often leaves out subject pronouns when the verb form already shows who the subject is.

Here, ćemo means we will, so we is already understood.
You could add mi for emphasis:

Mi ćemo se pobrinuti za prigovor. = We will take care of the complaint.

Without emphasis, leaving mi out is completely normal.

This is the future I tense.

It is formed with:

• a clitic form of htjeti (to want)
• • the infinitive of the main verb

In this sentence:

• ćemo = we will
• pobrinuti = infinitive, to take care / to see to

So literally, the structure is something like:

tomorrow + will-we + self + take-care + of the complaint

A useful thing to know: Croatian also allows the infinitive to come before the auxiliary:

• Pobrinut ćemo se za prigovor.

When that happens, the final -i of the infinitive is usually dropped in writing before ću/ćeš/će/ćemo...

Because the verb is pobrinuti se, not just pobrinuti.

This is a reflexive verb expression, and se is an unstressed reflexive particle. In this phrase, it is part of the normal dictionary form:

• pobrinuti se za nešto = to take care of something, to see to something

So you should learn it as a whole pattern:

• pobrinuti se za + accusative

In other words, se is not optional here.

This is mainly about aspect, which is very important in Croatian.

• brinuti se = imperfective
• pobrinuti se = perfective

The perfective verb pobrinuti se suggests a complete, one-time action: we’ll deal with it / we’ll take care of it.

That fits well with tomorrow, where the idea is that the matter will be handled.

By contrast, brinuti se usually suggests an ongoing state or repeated action, more like to worry, to care, or to be concerned in a continuing sense.

So in this sentence, pobrinuti se is the natural choice.

Because the verb pattern is:

pobrinuti se za + accusative

So za is required by this expression.

Many Croatian verbs and verb phrases have fixed prepositions, and you often need to learn them together. Here are some examples of the same pattern:

• pobrinuti se za djecu = take care of the children
• pobrinuti se za problem = deal with the problem
• pobrinuti se za prigovor = take care of the complaint

So the za is not just a freely chosen preposition; it belongs to the construction.

Prigovor is in the accusative singular because it follows za in this expression.

But it looks the same as the nominative because prigovor is a masculine inanimate noun.

For many masculine inanimate nouns in Croatian:

• nominative singular = accusative singular

So:

• nominative: prigovor
• accusative: prigovor

That is why the form does not visibly change.

Putting sutra first is very natural because Croatian often places time expressions near the beginning.

This gives the sentence a clear time frame right away:

• Sutra ćemo se pobrinuti za prigovor. = Tomorrow, we’ll take care of the complaint.

It could appear elsewhere too, for example:

• Ćemo se sutra pobrinuti za prigovor is not natural because of clitic placement
• Pobrinut ćemo se za prigovor sutra. is possible
• Mi ćemo se sutra pobrinuti za prigovor. is also possible

So sutra at the start is a very normal and common word order.

Yes, Croatian word order is fairly flexible, but not completely free.

The main thing to watch here is that ćemo and se are clitics. Clitics are short unstressed words that tend to appear early in the sentence and follow special placement rules.

So these are natural:

• Sutra ćemo se pobrinuti za prigovor.
• Mi ćemo se pobrinuti za prigovor sutra.
• Pobrinut ćemo se za prigovor sutra.

The meaning stays broadly the same, but the emphasis changes a little.

A good rule for learners is:
don’t move ćemo and se around too freely; keep them in the usual Croatian patterns.

Both are correct.

You will see two common future patterns:

• ćemo se pobrinuti
• pobrinut ćemo se

They mean the same thing. The difference is mostly in word order and style.

Important spelling point:

• when the auxiliary comes first: ćemo pobrinuti
• when the infinitive comes first: pobrinut ćemo

So the infinitive loses its final -i before the future auxiliary in writing.

That spelling detail often confuses learners, but both versions are standard.

It is best to learn the whole pattern:

pobrinuti se za + accusative

That will help you produce correct Croatian more naturally.

For example:

• pobrinuti se za dokumente
• pobrinuti se za goste
• pobrinuti se za prigovor

Learning verb + reflexive particle + preposition together is often the safest approach in Croatian.