He has much to answer for and she intends to show him for all to see the real monster that he is, she knows that a kiss would be far too easy for him, even if the Dementors that she has befriended would be in favor of it. They would rejoice at the chance to devour such a soul. Death wouldn’t be appreciative of that fate. He has brought up the way in which the afterlife works and Morgana is very content with him having a soul in which to play around with and torment.