거울이 존재하는 한 나의 춤을 못 막는다
As long as the mirror exists, No one can stop my dance.
거울이 존재하(다) + 는 한 + 나의 춤을 못 막는다
V-는 한 is an expression used to show that what comes in the preceding clause acts as a condition for what comes in the following clause. It can be understood in English as “as long as”.
e.g.
내가 살이 있는 한 이 결혼은 절대 못해! As long as I’m alive, this marriage will never happen!
학생이 한 명이라도 있는 한 수업해요. As long as there is even one student, there will be class.