YOU SAID:

Me think you not smart

INTO JAPANESE

私はあなたが賢くないと思います

BACK INTO ENGLISH

I don't think you're smart

INTO JAPANESE

私はあなたが賢いとは思わない

BACK INTO ENGLISH

I don't think you are smart

INTO JAPANESE

そんなはず ないだろ

BACK INTO ENGLISH

I don't think you are.

INTO JAPANESE

そんなはず ないだろ

BACK INTO ENGLISH

I don't think you are.