zimu ha muzukasii.

It is read:

じむ は むずかしい。

A few pronunciation notes:

• 事務 = じむ
• は is written ha, but when it is the topic particle, it is pronounced wa
• 難しい = むずかしい

So the whole sentence sounds like:

Jimu wa muzukashii.

Because は has a special pronunciation when it is used as a particle.

• As a normal syllable in a word, は is usually read ha
• As the topic particle, it is read wa

So in this sentence:

• 事務は = jimu wa

This is something you just have to get used to in Japanese spelling and grammar.

は marks the topic of the sentence.

So 事務は難しい means something like:

• As for office work, it’s difficult
• Office work is difficult

The topic is 事務. Then the sentence gives information about that topic: 難しい.

This is a very common Japanese pattern:

• X は Y
• As for X, it is Y

Both can be correct, but the nuance is different.

• 事務は難しい = As for office work, it’s difficult
  This sounds like you are talking about office work as a topic.

• 事務が難しい = Office work is the thing that is difficult
  This can sound more like identifying what is difficult, often in contrast with something else.

For many beginner sentences, は is used because it is a straightforward way to introduce a topic.
So 事務は難しい is a very natural basic sentence.

難しい is an い-adjective.

That means:

• it ends in い
• it can directly describe a noun, or it can end a sentence by itself

Examples:

• 難しい仕事 = a difficult job
• 仕事は難しい = The job is difficult

In your sentence, 難しい is being used as the predicate at the end of the sentence.

Because 難しい can end the sentence by itself in the plain form.

So:

• 事務は難しい。 = plain / casual style
• 事務は難しいです。 = polite style

With い-adjectives, you do not add plain だ at the end.

So these are correct:

• 難しい
• 難しいです

But not:

• 難しいだ ✘

Because Japanese sentences often place the main statement at the end.

In English, you say:

• Office work is difficult

In Japanese, the structure is more like:

• As for office work, difficult

So the adjective 難しい comes at the end because it is the main predicate of the sentence.

This is normal Japanese word order.

事務 usually means:

• office work
• clerical work
• administrative work

It refers to the kind of work done in an office, especially paperwork, routine administrative tasks, and related duties.

So depending on context, the sentence could mean:

• Office work is difficult
• Clerical work is difficult
• Administrative work is difficult

Not exactly in the English sense. Japanese often leaves out things that are understood from context.

The sentence only explicitly says:

• As for office work, difficult

In natural English, we add something like it is:

• Office work is difficult

Japanese does this all the time. If the meaning is clear from context, words like it, I, you, or they are often omitted.

Usually no. 事務 refers to office work or administrative duties, not the physical office itself.

For the physical office, you would more often see words like:

• オフィス
• 事務所 = office / business office

So in 事務は難しい, 事務 is about the work, not the building or room.

Japanese does not use articles like English does.

So 事務は難しい does not directly tell you whether it means:

• office work is difficult
• the office work is difficult
• this kind of office work is difficult

The exact English translation depends on context.

For a basic vocabulary or grammar example, Office work is difficult is the most natural translation.

Yes, grammatically it is natural.

However, by itself it sounds a little general, like a broad statement:

• Office work is difficult

In real conversation, Japanese often includes context, such as:

• 事務の仕事は難しいです。 = Office work is difficult.
• 事務は意外と難しい。 = Office work is surprisingly difficult.

But as a simple example sentence, 事務は難しい。 is perfectly fine.