YOU SAID:

i need to buy a cookie for my mother in order to eat fish

INTO JAPANESE

私は魚を食べるために母のためにクッキーを買う必要があります

BACK INTO ENGLISH

I need to buy cookies for my mother to eat fish

INTO JAPANESE

母が魚を食べるためにクッキーを買う必要がある

BACK INTO ENGLISH

Mother needs to buy cookies to eat fish

INTO JAPANESE

母は魚を食べるためにクッキーを買う必要がある

BACK INTO ENGLISH

Mother needs to buy cookies to eat fish