این سوال آسان بود، اما آن سوال از این سخت تر بود.

They are demonstratives:

• این = this
• آن = that

So:

• این سوال = this question
• آن سوال = that question

In everyday spoken Persian, آن is often said as اون.

Persian does not have an obligatory definite article like English the.

A noun can be definite from context, and words like این and آن already make it specific:

• این سوال = this question
• آن سوال = that question

So there is no need for a separate word meaning the.

بود is the past tense of to be: was.

In Persian, the verb usually comes at the end of the clause. So instead of English word order like This question was easy, Persian uses:

• این سوال آسان بود
• literally: this question easy was

That final position for the verb is very normal in Persian.

Because آسان is not directly modifying سوال inside the noun phrase here. It is the predicate adjective of the sentence.

So the structure is:

• این سوال = the subject
• آسان = the description
• بود = was

That means This question was easy.

If you wanted to say the easy question as one noun phrase, then you would use ezafe:

• سوالِ آسان = the easy question

So:

• این سوال آسان بود = This question was easy
• این سوالِ آسان = this easy question

Persian usually forms the comparative by adding -تر to an adjective.

Examples:

• سخت = hard
• سخت‌تر = harder

So تر works a lot like English -er in harder, smaller, faster.

In careful writing, this is ideally written with a نیم‌فاصله (half-space):

• سخت‌تر

But many texts also write it as:

• سخت تر

Both are very common in practice.

In Persian, the thing you compare against is usually introduced by از, which means from in many contexts, but in comparisons it works like than.

So:

• از این سخت‌تر = harder than this

That is the normal Persian comparative pattern:

• adjective + تر + از ...
• or in natural order inside a sentence, something like X از Y سخت‌تر است/بود

Here از این means than this one.

Because Persian often omits a repeated noun when it is obvious from context.

So in:

• آن سوال از این سخت‌تر بود

این really means this one or this question.

You could say از این سوال if you wanted to be extra explicit, but it is usually unnecessary because سوال has already been mentioned and is easy to understand.

Yes. سوال is a very common modern spelling, and سؤال is a more traditional spelling of the same word.

Both mean question.

A few notes:

• سوال is extremely common in everyday writing.
• سؤال may appear in more formal or older-style writing.
• Another Persian-based word is پرسش, which is also correct, but often sounds a bit more formal or literary.

So for learners, سوال is a very useful everyday word.

Yes. اما and ولی both mean but.

In this sentence, you could replace اما with ولی:

• این سوال آسان بود، ولی آن سوال از این سخت‌تر بود.

The difference is mostly about style:

• اما often sounds a bit more formal or written
• ولی is very common in speech and everyday conversation

Both are correct.

A very natural spoken version would be:

• این سوال آسون بود، ولی اون سوال از این سخت‌تر بود.

Common spoken changes:

• آسان often becomes آسون
• آن often becomes اون
• اما often becomes ولی

So the original sentence is perfectly correct, but the spoken version may sound more natural in daily conversation.

No. Persian adjectives do not change for masculine/feminine gender, and they usually do not change form for singular vs. plural either.

So آسان and سخت stay the same form regardless of the noun.

That is much simpler than in many languages. You do not need to memorize different adjective endings to match the noun.