YOU SAID:

Never coming back, boy

INTO JAPANESE

少年は決して戻って来てください。

BACK INTO ENGLISH

The boy is never coming back.

INTO JAPANESE

少年は戻ってこない。

BACK INTO ENGLISH

He does not come back.

INTO JAPANESE

彼は戻ってこない。

BACK INTO ENGLISH

He will come back.

INTO JAPANESE

彼は戻ってくるでしょう。

BACK INTO ENGLISH

He will come back.