اتفقنا. رائع! هذا يناسبني.

In Arabic, the past tense is often used for actions that are considered completed. So اتفقنا literally means we agreed, but in context it can function like English Agreed, It’s settled, or We have a deal.

This is very natural in Arabic. The idea is that the agreement has already been reached, so Arabic expresses it as a completed action.

Breakdown:

• اتفق = he agreed / came to an agreement
• اتفقنا = we agreed

So even if English might use a present-style expression, Arabic often uses the past here.

The ending -نا means we.

So:

• اتفق = he agreed
• اتفقنا = we agreed

This -نا is a very common suffix in past-tense verbs.

Examples:

• كتبنا = we wrote
• ذهبنا = we went
• فهمنا = we understood

In اتفقنا, it tells you the subject is we.

It is pronounced approximately ittafaqnā.

A helpful breakdown is:

• اِتَّ = itta
• فَقْ = faq
• نا = nā

So the whole word is:

• اِتَّفَقْنَا = ittafaqnā

A few pronunciation notes:

• The first vowel is a short i sound.
• The ت is doubled, so it is pronounced more strongly: tt
• The final نا has a long ā

رائع is originally an adjective meaning wonderful, great, or excellent. But like many adjectives in Arabic, it can be used on its own as an exclamation.

So:

• رائع! = Wonderful! / Great!

This is very similar to English, where an adjective can stand alone as a reaction.

You may also hear:

• ممتاز! = excellent
• جيد جدًا! = very good
• عظيم! = great

So in this sentence, رائع! is just a natural enthusiastic reaction.

هذا means this and is masculine singular.

In هذا يناسبني, it usually refers to:

• a plan
• a time
• an arrangement
• a suggestion
• something just mentioned

Arabic often uses هذا even when English might say that works for me or that suits me, depending on context.

Because the noun being referred to is often something masculine or an unstated idea like this arrangement, هذا is a natural default choice here.

If the thing referred to were clearly feminine, you would use هذه instead:

• هذه تناسبني = this suits me

يناسبني can be broken into two parts:

• يناسب = suits / fits / is suitable for
• ني = me

So:

• يناسبني = it suits me / it works for me

More literally:

• ي at the beginning marks the verb as third-person masculine singular in the present tense: he/it suits
• ناسب is the verb root pattern here
• ني is the attached object pronoun meaning me

So the full structure is:

• هذا يناسبني = this suits me

In the present tense, Arabic verbs often begin with a prefix that shows the subject.

In يناسب, the يـ means the subject is he or it.

Since هذا means this, Arabic treats it grammatically as a third-person masculine singular subject, so the verb is:

• هذا يناسبني = this suits me

Compare:

• هو يناسبني = it/he suits me
• هذا يناسبني = this suits me

If the subject were feminine, the verb would change:

• هذه تناسبني = this suits me

Yes, you could, and it is similar in meaning.

Comparison:

• هذا يناسبني = this suits me / this works for me
• هذا مناسب لي = this is suitable for me

The difference is mainly one of style and nuance:

• يناسبني uses a verb and often sounds a bit more dynamic or personal
• مناسب لي uses an adjective and sounds a bit more descriptive

Both are correct in Modern Standard Arabic. In many contexts, either one would be understood naturally.

More literally, it is this suits me.

That is because يناسبني is a verb:

• يناسب = suits
• ني = me

If you wanted the more literal structure this is suitable for me, Arabic would usually use something like:

• هذا مناسب لي

So the sentence you have is verbal, not adjectival.

Yes, it is natural and clear in Modern Standard Arabic:

• اتفقنا. = Agreed. / We agreed.
• رائع! = Great!
• هذا يناسبني. = This suits me. / This works for me.

It sounds like polite, standard Arabic and would fit well in writing, formal conversation, or semi-formal speech.

In everyday spoken dialects, people might use different expressions depending on the country, but this MSA version is perfectly good and understandable.

Usually, in normal modern writing and everyday pronunciation of Modern Standard Arabic, you do not pronounce full case endings unless you are reading very carefully or in a highly formal setting.

So you would normally say:

• اتفقنا
• رائع
• هذا يناسبني

without adding formal case endings at the ends of words.

In fully vocalized formal Arabic, some endings could appear in careful recitation, but for most learners and most real-life use, the simpler pronunciation is what you will hear and use.