YOU SAID:

I ain't never seen two pretty best friends, its always one of em gotta be ugly

INTO JAPANESE

私は2人のかなりの親友を見たことがありません、それはいつも醜いものでなければなりません

BACK INTO ENGLISH

I've never seen two pretty best friends, it must always be ugly

INTO JAPANESE

私は2人のかなり親友を見たことがありません、それはいつも醜いに違いありません

BACK INTO ENGLISH

I've never seen two pretty best friends, it must always be ugly