YOU SAID:

It doesn't even matter how hard you try

INTO JAPANESE

どんなに一生懸命やっても構わない

BACK INTO ENGLISH

I don't care how hard you try.

INTO JAPANESE

君がどれだけ一生懸命やってみようとしてもかまわない。

BACK INTO ENGLISH

I don't know how hard you try.

INTO JAPANESE

私はあなたがどれほど一生懸命やっているのか分かりません。

BACK INTO ENGLISH

I don't know how hard you're trying.

INTO JAPANESE

君がどれだけ一生懸命やっているのか分からない。

BACK INTO ENGLISH

I don't know how hard you're trying.