YOU SAID:

I did not know that this was a thing

INTO JAPANESE

私はこれが事だったことを知らなかった

BACK INTO ENGLISH

I didn't know this was the thing

INTO JAPANESE

お前も　そういうの趣味あるんだ

BACK INTO ENGLISH

I didn't know that was your thing.

INTO JAPANESE

お前も　そういうの趣味あるんだ

BACK INTO ENGLISH

I didn't know that was your thing.