Japanase language is the second most difficult language in the world to learn. To make a conversation in other language needs not only to learn the sentence patters and grammers but also needs to understand the nuances of the language as well as culture from which it is derived or based.

Today we are going to learn how to say I agree with you in Japanese in various ways.

I agree.

賛成です(sansei desu).

Sansei means 'Approval', 'Agreement', 'Support' that shows support towards whatever the speaker is saying. Mostly this word used at formal occasion

Absolutely.

全くその通り(Mattaku sono tōri).

It means "Just like that!". Let me give you an example. When someone says, "Are you a Teacher.!" then answer would be "Exactly, I'm a Teacher"

Of course

もちろんです(Mochiron desu).

Mochiron means of course, certainly, naturally. This phrase is generally used to introduce an idea or action which is obvious.

e.g.
ご一緒してもいいですか。もちろんです。 goisshou shitemo iidesuka. mochironndesu. "May I go with you?" "of course." Look at one more example. e.g. "‘Can I see you for a minute?’ ‘Of course.’"

No doubt about it.

間違いありません(Machigai arimasen)

It used to indicate the speaker's firm belief that something is true.

e.g 彼の成功は間違いない。 kare no seikou ha machigainai I have no doubt that he will succeed.

Maybe.

多分ね(Tabun ne)。

Tabun means May be, perhaps and is used to admit the truth of a point in an argument before introducing another, more important point.

e.g. 多分彼は悪い子ではないと思います。 tabun kare ha waruiko devanai to omoimasu. I think that he's probably not a bad boy.

I have the same opinion.

同じ意見です(Onaji iken desu)。

If two people are of the same mind, they have the same opinion and so agree with one another. ... If you agree to support someone's opinion, even though you may not agree fully with them, you can say that you will go along with them.

e.g. 私もあなたと同じ意見です。 watashi mo anata to onaji iken desu. I have the same opinion as you

I guess so.

そういうことだと思う(Sou iu koto da to omou)。

Often used as an affirmative answer when one is not completely certain or does not want to fully commit. A: "Did you have a good time?" B: "I guess so." A: "It's supposed to be sunny today, right?" B: "I guess so.

e.g 彼女はそういうことを知って安心したいだけだと私は思う。 kanojo va souiukoto wo shitte anshin shitai dake dato watashi va omou. I think she just wants to be relieved to know that.

You may be right.

あなたが正しいかもしれない。 Anata ga tadashii kamoshirenai.

Such a phrase is used as saying when you're right, you're right is a way to tell someone that although you'd like to disagree with him or her, you can't, because he or she is objectively correct.

e.g. あなたの言うことは正しいかもしれない。 anata no iu koto va tadashii kamoshirenai. You could be right, I suppose.

Yes, you’re right, I think.

はい、正しいと思います(Hai, tadashii to omoimasu)。

Such phrases are used to tell the speaker that what you have said, I also thinks the same way.

Sounds good!

それは、いいね！(Sore wa, ii ne!)

Used for telling someone that their idea or suggestion seems like a good one. 'How about dinner and a film tonight? ' 'Sounds great. '