YOU SAID:

i wont look a gift horse in the mouth

INTO JAPANESE

私は口の中で贈り物の馬を見ない

BACK INTO ENGLISH

I don't see a gift horse in my mouth

INTO JAPANESE

贈り物の馬が口の中に見えない

BACK INTO ENGLISH

The horse of the gift is not visible in the mouth

INTO JAPANESE

贈り物の馬は口の中に見えません

BACK INTO ENGLISH

The horse of the gift is not visible in the mouth