YOU SAID:

hey want to go shopping with me this sunday

INTO JAPANESE

ねえ、今度の日曜日一緒に買い物に行きたいんだけど

BACK INTO ENGLISH

Hey, I'd like to go shopping with you next Sunday.

INTO JAPANESE

ねえ、次の日曜日に一緒に買い物に行きたいのですが。

BACK INTO ENGLISH

Hey, I'd like to go shopping with you next Sunday.