Nadam se da će ti ove nove riječi pomoći na ispitu i u budućem životu u gradu.

You need "se" because the verb is reflexive: the dictionary form is nadati se = to hope.

• Nadam se literally = I hope (myself), but in English we just say I hope.
• Nadam without se is wrong in standard Croatian in this meaning; it would sound incomplete.

So:

• ✅ Nadam se da će… = I hope that…
• ❌ Nadam da će… (ungrammatical in standard usage)

Yes. Da introduces a subordinate clause, very much like English "that".

• Nadam se da će ti ove nove riječi pomoći…
  = I hope *that these new words will help you…*

After nadam se, when you’re saying what you hope will happen, you essentially always use da + a finite verb:

• Nadam se da će doći. – I hope (that) he/she will come.

You normally do not use an infinitive there, so "Nadam se pomoći" is not natural Croatian.

Će is the future tense auxiliary, similar to English "will".

The pattern is:

• ću, ćeš, će, ćemo, ćete, će
  • infinitive

In the sentence:

• će = 3rd person singular future auxiliary (will)
• pomoći = infinitive (to help)

So (one) će pomoći = it/they will help.

Because "ove nove riječi" (these new words) is the subject, the meaning is:

• Ove nove riječi će ti pomoći.
  = These new words will help you.

Both are correct; the difference is mostly word order preferences in subordinate clauses.

1. Given version (inside the "da" clause):

   • da će ti ove nove riječi pomoći
   • After da, the clitics (short unstressed words) move into second position:
     • će (auxiliary)
     • ti (short pronoun)
   • Then comes the rest: ove nove riječi (subject) + pomoći (main verb).

2. Alternative main-clause style word order:

   • Ove nove riječi će ti pomoći.
   • Very natural, especially as a standalone sentence.

Inside a da-clause, it’s very typical (and strongly preferred) to put the clitics (će, ti, etc.) right after da or after the first accented word. So:

• ✅ Nadam se da će ti ove nove riječi pomoći.
• ❌ Nadam se da ove nove riječi će ti pomoći. (sounds wrong)

Ti here is the short dative form of "you".

• Full (stressed) form: tebi (dative)
• Short (clitic) form: ti (dative)

The verb pomoći takes a dative object:

• pomoći (kome? čemu?) – to help whom / to help to whom

So:

• Ove nove riječi će ti pomoći.
  = These new words will help *you (to you).*

You don’t use te, tvoj, etc. here; ti is exactly the right dative pronoun.

Because "riječ" (word) is feminine, and here it’s plural and nominative (subject).

• Noun: riječ – feminine
• Plural nominative: riječi

The demonstrative and the adjective must agree with the noun in gender, number, and case:

• ove – feminine plural nominative/accusative of ovaj/ova/ovo (this/these)
• nove – feminine plural nominative/accusative of nov (new)
• riječi – feminine plural nominative/accusative

Together, ove nove riječi = these new words (subject of the clause).

Forms like ovi novi riječi are wrong because ovi/novi are masculine plural forms.

In this sentence, "riječi" is plural.

• Singular:

  • Nominative: riječ – a word
  • Genitive: riječi – of a word

• Plural:

  • Nominative: riječi – words
  • Accusative: riječi – words (same as nominative for inanimate nouns)

Here ove nove riječi is the subject (these new words), so we interpret riječi as plural nominative, agreeing with ove and nove (also plural).

Because "na ispitu" uses the locative case, which is used with na when you are talking about being at or during something (not movement towards it).

• na + locative → location/time:
  
  • na ispitu – at the exam / in the exam / during the exam
• na + accusative → movement onto/into:
  
  • ići na ispit – to go to the exam

So:

• pomoći na ispitu = help (you) in/at the exam
• If you said pomoći na ispit, it would sound like helping “onto/to the exam”, which is wrong here.

They express different ideas:

• na ispitu (locative)

  • Literally: on/at the exam
  • Meaning: during the actual exam situation
  • pomoći ti na ispitu – help you during the exam

• za ispit (accusative)

  • Literally: for the exam
  • Often about preparation/benefit for the exam
  • učiti za ispit – to study for the exam
  • riječi za ispit – words for the exam (useful for the exam)

In your sentence, na ispitu is correct because the idea is “help you during the exam”.

Because "u budućem životu" is locative, used with u when talking about being in a state or period, not moving into it.

• u + locative → being in/inside:

  • u budućem životu – in (your) future life

• u + accusative → movement into:

  • u budući život would mean something like into a future life (movement), which is not what is meant here.

Also, budućem agrees with životu in gender, number, and case:

• život – masculine singular
• Locative: u životu
• Adjective budući → locative masculine singular: budućem

So u budućem životu = in (your) future life.

Because Croatian future tense with ću/ćeš/će… is normally formed with the auxiliary + infinitive:

• će pomoći – will help
• not će pomogne / će pomognu.

So:

• Ove nove riječi će ti pomoći.
  = These new words will help you.

Also, pomoći is perfective; it focuses on the result (that the help will succeed).
The imperfective form is pomagati (to be helping, to help repeatedly). In this context, the result is more important, so pomoći is natural.