In Pokemon White, can a pokemon learn a move it gave up with the relearn service?

Yes, the lady who a Pok�mon re-learns moves from can help any Pok�mon return any previous moves that it did not get regardless of whether it was deleted, skipped or the Pok�mon just didn't get a chance to learn it due to evolving too late via leveling up. This will not let you remember moves that it cannot learn anymore in Pok�mon White but they could learn in the previous games. The moves in question must be level-up moves. Golett can learn Curse now or not, that's your call. Because it's a level-up move, the lady will be able to give it to Golett later on if you don't want Golett to have it now. You do not need Golett to know Curse now for it to be available from the Move Tutor who is responsible for re-learning the moves.