어야 나오다

it only comes out once X

A condition that has to be satisfied before something appears, and 나오다 covers several kinds of appearing here: a product being released only later, a benefit paid out only after twelve months of work, something showing up only if you look closely or search the right words, a contract term having to run out first. It also stretches to a performer, who says the good stuff only comes out when the people around her draw it out.