Ubojica zna svoju sudbinu.

Because svoju is the reflexive possessive form, meaning one’s own.

In Ubojica zna svoju sudbinu, the owner of the fate is the subject, ubojica. So Croatian normally uses svoj:

• Ubojica zna svoju sudbinu = The murderer knows his own fate.

If you said njegovu sudbinu, it would usually mean someone else’s fate, not the murderer’s own.

This is a very important Croatian pattern:

• subject owns something → use svoj
• someone else owns it → use njegov / njezin / njihov, etc.

Because svoju has to agree with sudbinu in gender, number, and case.

Here:

• sudbina = feminine singular noun in the dictionary form
• in this sentence it becomes sudbinu = accusative singular
• so svoj must also become the matching form svoju

So the pair is:

• svoja sudbina = nominative
• svoju sudbinu = accusative

This agreement is normal in Croatian adjectives and possessives.

Because it is the direct object of the verb zna.

The verb znati means to know, and the thing that is known goes in the accusative:

• zna sudbinu = knows the fate
• vidi čovjeka = sees the man
• ima knjigu = has a book

So in this sentence:

• Ubojica = subject
• zna = verb
• svoju sudbinu = direct object in the accusative

Zna is the 3rd person singular present tense of znati.

The verb forms are:

• ja znam = I know
• ti znaš = you know
• on/ona zna = he/she knows

Since ubojica is singular, the sentence uses zna.

Not necessarily. This is a very common learner question.

Although ubojica ends in -a, it can refer to a male murderer, and nouns like this are often treated as masculine by meaning even though they look like many feminine nouns.

So the ending -a does not always mean feminine in Croatian.

Other nouns like this exist too, especially for people:

• sudac is not one of them, but
• vođa, sluga, ubojica are good examples of person nouns that may not match the usual ending pattern learners expect.

In this sentence, ubojica is the subject in the nominative singular.

The dictionary forms are:

• ubojica = murderer / killer
• znati = to know
• svoj = one’s own
• sudbina = fate / destiny

In the sentence, the changed forms are:

• zna from znati
• svoju from svoj
• sudbinu from sudbina

Because Croatian normally does not use articles.

English says:

• the murderer
• a murderer

Croatian usually just says:

• ubojica

Whether it means the murderer, a murderer, or even murderer in a more general sense depends on context.

So Ubojica zna svoju sudbinu can be understood naturally without any article.

Yes. Croatian word order is more flexible than English word order because the case endings show the grammatical roles.

The neutral, straightforward order here is:

• Ubojica zna svoju sudbinu.

But you could also hear:

• Svoju sudbinu zna ubojica.
• Ubojica svoju sudbinu zna.

These alternatives can sound more emphatic, poetic, or contrastive depending on context.

Even though the order can change, the endings still show that:

• ubojica is the subject
• svoju sudbinu is the object

Because znati is the normal verb for knowing a fact, truth, or piece of information.

Here, one’s fate is something known mentally, so znati fits well:

• zna svoju sudbinu = knows his own fate

Poznavati is more often used for being familiar or acquainted with:

• a person
• a place
• a field of knowledge

For example:

• Poznajem tog čovjeka. = I know that man.
• Dobro poznaje Zagreb. = He knows Zagreb well.

So in this sentence, znati is the natural choice.

Very literally, it is:

• Ubojica = murderer
• zna = knows
• svoju = his/her own
• sudbinu = fate

So the structure is basically:

• Murderer knows his-own fate.

That literal breakdown helps show why svoju is so important: it links the fate back to the subject.