I'm not sure that is a very meaningful text, but I'll try to give my interpretation. I'd say the promise [of the guy to steal the girl] is about two possible outcomes: it could either end with the happy life together (aka "На любовь") or with the bitter separation when they find out they are not the most perfect match together (aka "на беду"). Either way, the guy does not really care at this very moment only thinking about how much he desires the girl.