I want to make an neutral evil wizard swear to be my teacher in exchange for saving his life. Is there a spell or something to make him keep his word? Are there options if he is from another magic class, like sorcerer or warlock?
They are both Drows so I was thinking of making him swear to Lolth, but I don't think that would stop him from betraying me. This is only roleplay oriented, so that I can pick up a second class.