The effect is rather simple, its an ink change than a reverse torn and restored card. By that I mean a card with a heart drawn on it is shaken and the heart then breaks apart. This can easily go along with any story of a girl (or guy) you loved breaking your heart. The ink change can be done in many different ways even without a gimmick but after the ink changes the card then breaks apart. I don't know if it would tear itself or simply just wither away or maybe even fold itself, but the basic idea of the heart on the card breaking and then the card itself breaking sounds like it could be very powerful. This can then be followed up with restoring the card with a dupe of the original heart card or just even the original heart card to end on a happy note of the heart not being completely broken.

The ink change is easy but I have no idea how to make a card tear itself apart. There's ways to do it fast and visual (like shin lim who turns cards into confetti) but I don't think a fast visual tear would fit the dark slow mood of the rest of the trick very well so a slow animated tear or wither or what ever would work the best. Honestly it doesn't even need to be on a playing card... if a drawing of a heart or a heart shaped piece of paper works better than do that.