YOU SAID:
she is so slaying that outfit
INTO JAPANESE
彼女はその衣装をとても気に入っています
BACK INTO ENGLISH
she likes that outfit
INTO JAPANESE
彼女はその服装が好きです
BACK INTO ENGLISH
she likes that dress
INTO JAPANESE
彼女はそのドレスが好きです
BACK INTO ENGLISH
she likes that dress
That didn't even make that much sense in English.