YOU SAID:

all I wanna do is she at Costco

INTO JAPANESE

私がしたいのはコストコにいる彼女だけです

BACK INTO ENGLISH

All I want is her at Costco

INTO JAPANESE

私が欲しいのはコストコの彼女だけです

BACK INTO ENGLISH

All I want is a Costco girlfriend

INTO JAPANESE

私が欲しいのはコストコのガールフレンドだけです

BACK INTO ENGLISH

All I want is a Costco girlfriend