YOU SAID:

be nice or someone will not be nice

INTO JAPANESE

親切でなければ、誰かが親切ではない

BACK INTO ENGLISH

If it's not kind, someone's not kind.

INTO JAPANESE

親切でなければ、誰か親切ではない。

BACK INTO ENGLISH

If not kind, then no one is kind.

INTO JAPANESE

親切でなければ、誰も親切ではない。

BACK INTO ENGLISH

No one is kind unless they are kind.

INTO JAPANESE

親切でなければ誰も親切ではない。

BACK INTO ENGLISH

No one is kind unless they are kind.