Chill for 50 minutes, then check every 5 minutes until gelatin is partially set. Gelatin is ready when you can still stick your finger in it, but it will feel thick and heavy.

If you can't find candy hearts, make your own hearts with red-hot dollars while gelatin thickens. 

To make: place 1 red-hot dollar between 2 pieces of waxed paper, and roll thin (1/8") with a rolling pin or can and use a small heart cookie cutter, or scissors to cut a heart out of the candy.