YOU SAID:
dont judge a book by it's cover
INTO JAPANESE
それが表紙で本を判断してはいけない
BACK INTO ENGLISH
Do not judge the book by the cover
INTO JAPANESE
表紙で本を判断しない
BACK INTO ENGLISH
Do not judge the book on the cover
INTO JAPANESE
表紙の本を判断しない
BACK INTO ENGLISH
Do not judge the book on the cover
That didn't even make that much sense in English.