YOU SAID:

I will get a new shirt, I promise.

INTO JAPANESE

新しいシャツを買うよ、約束するよ。

BACK INTO ENGLISH

I'll buy you a new shirt, I promise.

INTO JAPANESE

新しいシャツを買ってあげるよ、約束するよ。

BACK INTO ENGLISH

I'll buy you a new shirt, I promise.