Probably not, the best part of love is coming to realization that you want to be with this person forever, and that you want to end up with them.
But if you know, i'd think it'd kill a lot of the relationship, i mean you'd know you'd end up together, so why bother with all the wooing and courting.
Yes.I would then at least know I won't be lonely my whole life. It's just not good enough having someone tell me that there's someone out there for me.