That quest is an ongoing quest and cannot be finished. The quest was completed and you received your reward when you turned in your very first heart.
It pays to mindread him before you turn in that first heart. The quest pays off the mindreading cost and from then on, you get triple gold and exp for each heart you turn in.
I'd like to close by quoting Bellegar's famous last rhyme:
"Cursed be the mother that bred thee! The wench must have been a hell-spawned banshee!"
