Bewitched, Bothered And Bewildered - S2-E16
Corrected entry: Amy refers to Diana as goddess of love. The correct goddess of love would be either Aphrodite for the Greeks or Venus for the Romans. Diana was goddess of the hunt, virginity, and childbirth.
Correction: Amy says that for a love spell to work requires pure intent. The spell she casts causes Obsession rather than Love, therefore a goddess of The Hunt would be more appropriate than the goddess of Love. (She's also only been a witch for less than a year, so she's bound to make mistakes).
Captain Defenestrator