The Demon Lord's Fairy Bride

The man Liz Powell takes for her husband is the Demon Lord, and he is beside her because he wants the crystal heart in her chest. Liz is a flower fairy who read too many romance novels and paid the fortune fairy in spirit stones for a love trial down in the mortal world. She arrives, meets him, decides he is the husband she came for, and gives him everything she has. He goes for the heart more than once and stops short each time. Living next to her wears the intention down, and he carries the cold poison eating at him rather than cut her open. By the time the two of them are close to something, Liz learns who she has been keeping house for, and that killing her was the plan from the start.