賛成だ

agree with

phrase Uncommon #17,848
agree with Used to express agreement with an opinion, proposal, or idea. だ is the plain form; です is the polite form.
JA: 私はその計画に賛成だ。
EN: I agree with that plan.

彼はそれに賛成だという立場をとった。

He took the position that he was in favor of it.

私はあなたに賛成だ。

I agree with you.

その点では君に全面的に賛成だ。

I completely agree with you on that point.

私はその意見に賛成だ。

I agree with that opinion.

君に賛成だとしか言えない。

I can only say that I agree with you.

彼は賛成だと言わんばかりにうなずいた。

He nodded as if to say he agreed.

私はある程度は君に賛成だ。

I agree with you to some extent.