YOU SAID:
It is impossible for me to believe that this is not butter.
INTO JAPANESE
私はこれがバターではないと信じることは不可能です。
BACK INTO ENGLISH
I can not believe this is not butter.
INTO JAPANESE
私はこれがバターではないとは信じられません。
BACK INTO ENGLISH
I can not believe this is not butter.
That didn't even make that much sense in English.