Probably not, the best part of amor is coming to realization that tu want to be with this person forever, and that tu want to end up with them.
But if tu 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.