Key to My Heart is the 63rd episode of Sabrina the Animated Series.
Sabrina has a crush on Dave, her new piano instructor. She is devastated when she learns that he already has a lady in his life, Melinda. Sabrina is so jealous that she casts a spell to hurt Melinda's career so Dave can focus on her. It isn't until Dave abandons his own dreams to help Melinda does Sabrina realize what she has done. Sabrina has to give up something important to her in order to restore things to normal.