what will happen if jake and finn would be seperated???

Well I guess try to find a way back to each other, like anyone would. It's Ooo they can find each other again.

Refer too the episode where Finn was caught によって gnomes, All he did was worry, not really go psychotic.

Try looking for the answer in the episodes. They did get separated a few times, like in that dungeon and stuff. But yeah I'm going with Red's answer.

I think your 質問 means that Finn & Jake wouldn never ever see each other again like the time Finn was with Rosalinen, right?