Valentine heart strategy
Seem to be collectable from buildings associated with a character only.
Forum Discussion
As of now it seems you get the most hearts from your friends visiting you. I can only visit 11 of my friends right now but everyone seems to be able to visit me. Visiting others maybe I've gotten 12 or so hearts. However I've received almost 200 hearts from friends. I've collected most of my gifted hearts/cards via my friends from in game characters who are currently not assigned to a task.
