기방(Gibang) is the place where the geisha women lived and entertained their customers.
It's not a brothel, as geisha were professional entertainers trained in singing and dancing.
1. 화려한 기방에 데려 가준다지 않으셨습니까? (데려 가준다지 -> 데려가 준다지)
=> [화려한 기방에 데려가 준다지] 않으셨습니까? (준다지 = 준다고 (말)하지 = said that you would ...)
=> Didn't you tell me you'd take me to a fancy geisha house?
2. 방금 지나친 저쪽 기방이 정말 화려해 보이던데
[[방금 지나친] 저쪽 기방]이 정말 화려해 보이던데 (화려해 보이던데 = it looked great/gorgeous, so ...)
=> That geisha house we just passed looks really gorgeous to me.