Bila sam razočarana i nestrpljiva, jer je vlak kasnio skoro sat vremena.

Croatian often leaves out subject pronouns when they are already clear from the verb form. Here sam shows first person singular, so ja is not needed.

You could add it for emphasis:

Ja sam bila razočarana i nestrpljiva...

That would mean the same thing, but with more stress on I.

This is because sam is a clitic: a short, unstressed word that normally cannot stand at the beginning of a clause.

Croatian past tense is built with:

• the l-participle: bila
• the auxiliary biti: sam

So the meaning is basically was + I in structure, but the natural Croatian order is:

Bila sam

not Sam bila.

If you include the pronoun, you get:

Ja sam bila

which is also very natural.

They all agree with the speaker, who is understood to be female singular.

In Croatian, past participles and adjectives agree in:

• gender
• number
• sometimes effectively the understood subject

So here:

• bila = feminine singular
• razočarana = feminine singular
• nestrpljiva = feminine singular

If a man said the same sentence, it would be:

Bio sam razočaran i nestrpljiv, jer je vlak kasnio skoro sat vremena.

They are adjectives used with biti to describe a state:

• razočarana = disappointed
• nestrpljiva = impatient

So bila sam razočarana i nestrpljiva literally means something like:

I was disappointed and impatient

This is a very common Croatian structure:

• biti + adjective

For example:

• Bila sam umorna. = I was tired.
• Bio je ljut. = He was angry.

Because both adjectives belong to the same predicate:

bila sam razočarana i nestrpljiva

In English, this works the same way:

• I was disappointed and impatient not
• I was disappointed and was impatient unless you want special emphasis

So one sam is enough for both adjectives.

In standard Croatian, a clause introduced by jer is normally separated by a comma.

So:

Bila sam razočarana i nestrpljiva, jer je vlak kasnio skoro sat vremena.

This is standard punctuation.

Very often, English learners notice that Croatian uses commas a bit more systematically before subordinate clauses than English does.

Again, this is about clitic placement.

The word je is also a clitic, so it wants to appear very early in the clause. After jer, the normal order is:

jer je vlak kasnio

not jer vlak je kasnio.

As a standalone clause, you would say:

Vlak je kasnio.

But after jer, the standard order is:

jer je vlak kasnio

Kasnio is the masculine singular l-participle of the verb kasniti = to be late / to run late.

With the auxiliary je, it makes the past tense:

je kasnio = was late / was delayed

It is masculine singular because it agrees with vlak, which is a masculine singular noun.

Compare:

• Vlak je kasnio. = The train was late.
• Autobus je kasnio. = The bus was late.
• Tramvaj je kasnio. = The tram was late.

If the subject were feminine:

• Brodica je kasnila.

Croatian often expresses duration without any preposition. English says for almost an hour, but Croatian simply uses a duration phrase:

skoro sat vremena

So:

• kasnio skoro sat vremena = was delayed for almost an hour

This is very normal in Croatian.

Other examples:

• Čekao sam dva sata. = I waited for two hours.
• Spavala je cijeli dan. = She slept for the whole day.

This is a very common Croatian time expression.

• sat = hour
• vremena = of time

So sat vremena literally looks like an hour of time, but idiomatically it just means an hour.

This structure is very common with durations:

• sat vremena = an hour
• dva sata = two hours
• pet sati = five hours

In your sentence, skoro sat vremena means almost an hour.

Skoro means almost or nearly.

So:

• skoro sat vremena = almost an hour

Yes, gotovo can often be used too:

• gotovo sat vremena

Both are correct. In many everyday contexts, skoro feels a bit more conversational, while gotovo can sound slightly more formal or neutral, but the difference is usually small.

Yes. You could say:

Bila sam razočarana i nestrpljiva zato što je vlak kasnio skoro sat vremena.

Both jer and zato što mean because.

Very roughly:

• jer = shorter, very common, simple
• zato što = also very common, sometimes a bit more explicit

In this sentence, either one sounds natural.

Yes, Croatian word order is fairly flexible, but not all versions sound equally neutral.

The original sentence is very natural:

• Bila sam razočarana i nestrpljiva, jer je vlak kasnio skoro sat vremena.

You could also say:

• Ja sam bila razočarana i nestrpljiva... if you want to emphasize I
• Bila sam nestrpljiva i razočarana... if you want to foreground impatient
• Razočarana sam bila... but this sounds more marked or expressive

So yes, word order can change, but the original is a very good neutral model.