so-cosmic asked: I'm going to Germany in 8 days and I'm going to be there until Valentine's Day, so I was wondering, how do you say "Will you be my Valentine?" and other Valentines expressions?

Well, Valentine’s Day became popular in Germany after WWII because American soldiers brought their tradition here. The “Will you be my Valentine?” question is, at least as far as I know, something Germans don’t ask. Sure, there’s lots of card-writing, flower-giving etc. on that day and stores are decorated with e.g. hearts. But it’s not as important here as it is in the US.