지만 모르다

but still not know

-지만 grants something and then denies the knowledge you would expect to follow from it: same agency but strangers, family but full of stories you don't know, Korean but never knew this. Two lines use the standard hedge 다들 아시겠지만 모르시는 분도 계시니까 — most of you know this, but some don't — which is how speakers excuse themselves for explaining something basic.

Register: everyday; the hedge is polite