Ta część raportu jest trudna.

Word by word:

• ta = this
• część = part
• raportu = of the report
• jest = is
• trudna = difficult / hard

So the structure is basically:

• Ta część = this part
• raportu = of the report
• jest trudna = is difficult

Because część is a feminine noun, and Polish demonstratives must agree with the noun’s gender.

The singular forms are:

• ten = masculine
• ta = feminine
• to = neuter

Since część is feminine, you say:

• ta część

not:

• ten część
• to część

You mostly learn the gender with the noun, but there are also patterns.

Część is feminine even though it does not end in -a, which can surprise English speakers. Many feminine nouns in Polish do end in -a, but some feminine nouns end in a soft consonant or -ść, and część is one of them.

You can also see it from agreement:

• ta część
• trudna część
• ta część jest trudna

All the agreeing words are in the feminine form.

Because część often takes the genitive to mean part of something.

So:

• część raportu = part of the report
• literally: part [of] report

The base form is:

• raport = report

But after część, it changes to the genitive singular:

• raportu

This is a very common pattern in Polish:

• koniec filmu = the end of the film
• początek dnia = the beginning of the day
• środek miasta = the center of the city

Raport is a masculine noun. In the genitive singular, many masculine nouns take -u or -a, depending on the word.

Here:

• nominative: raport
• genitive: raportu

Unfortunately, whether a masculine noun takes -u or -a is something you often need to learn with the word. But raportu is the correct genitive form here.

Because adjectives must agree with the noun they describe.

Since część is feminine singular, the adjective also has to be feminine singular:

• masculine: trudny
• feminine: trudna
• neuter: trudne

So:

• ta część jest trudna

If the noun were masculine, you would say trudny. If it were neuter, you would say trudne.

Because after jest in this sentence, the adjective is in the nominative, not the accusative or instrumental.

So:

• Ta część jest trudna. = correct

not:

• Ta część jest trudną.

With być + adjective, Polish normally uses the adjective in the nominative:

• On jest zmęczony.
• Kawa jest gorąca.
• Ta część jest trudna.

Polish does not have articles like a or the.

So część raportu can mean:

• part of the report
• a part of the report

The exact meaning depends on context.

In this sentence, ta already gives you specificity, so ta część raportu clearly means this part of the report.

Yes. Polish word order is more flexible than English because case endings show grammatical relationships.

The most neutral order here is:

• Ta część raportu jest trudna.

But other orders are possible, for example:

• Ta część jest trudna. = This part is difficult.
• Trudna jest ta część raportu. = puts more emphasis on difficult
• Raportu ta część jest trudna. = possible in a marked or poetic/contextual style, but not the most natural neutral choice

Even when the order changes, the meaning often stays similar, but the focus or emphasis changes.

Normally, in standard Polish, no.

Polish usually keeps the present-tense form of to be:

• Ta część raportu jest trudna.

Leaving out jest would sound incomplete in normal standard speech.

This is different from some other Slavic languages where the present tense of to be can often be omitted.

Część is one of those words that looks harder than it is.

A rough guide:

• cz sounds like ch in chop
• ę is a nasal vowel; before ś/si in normal speech, it is often pronounced somewhat like en or a nasalized e
• ść sounds like a soft shch-type sound, but softer and more compact

A rough English-style approximation is something like:

• chen-shch or chenshch

But that is only approximate. The main thing is to notice:

• cz is one sound
• ś / ść is soft
• ę is nasal

Usually yes in the sense of difficult, not physically hard.

So in this sentence:

• trudna = difficult

It can be used for:

• difficult tasks
• difficult questions
• difficult parts of a text or report

For physical hardness, Polish often uses a different adjective:

• twardy / twarda / twarde = hard in the physical sense

So:

• Ta część raportu jest trudna = this part of the report is difficult
• not: this part of the report is physically hard

Usually część raportu is better here.

• część raportu = part of the report
• część z raportu can sound more like a part taken from the report or a section from the report, depending on context

So for the straightforward idea this part of the report, the most natural phrase is:

• ta część raportu

Yes, depending on what you mean.

Some possible alternatives:

• fragment raportu = a fragment/section of the report
• sekcja raportu = section of the report
• rozdział raportu = chapter of the report if it is divided that way

But część raportu is broad and natural. It simply means part of the report, without specifying exactly what kind of division it is.