The only way Belle will be staying in SB longer than the amount of time it takes to cloak the town is if something bad is going on there that she needs to stop. However, will she be able to leave? I’m assuming, even though there’s an antidote, the curse still occurs if you cross the town line, so who says you’ll remember to drink the antidote after you do and lose your memories, or if Blue has any more? Maybe Belle stays in SB studying magic until she can break that curse and go find Rumple. If she can leave, I think something will happen in SB to prevent it, like ex-king George making another power grab or THO somehow getting in (clearly they are not so against magic that they won’t sometimes use it). But I just think that K&H will want to keep her in SB to keep audience interest from completely being off SB, which is why I think they left her there in the first place. (And to keep Rumbelle fans in tension, of course.) Not that I think we’ll spend a lot of time there next season, but maybe the core cast will go back eventually.