Threads of Faith — Joey W. Hill

Marisa is a modern-day witch, living at the edge of the woods and of society. She dispenses potions to help lonely souls find their true loves. Because of her inability to live among others, she doesn't believe love is for her, let alone sexual fulfillment. Then Conlon Maguire shows up at her cottage. Conlon wants a potion to win the heart of his soulmate, but the magic behind the potion sets its price. Conlon's potion demands that he spend one night with Marisa, bringing her pleasure. As a servant of the Light, Marisa cannot refuse the price if Conlon agrees to it, but from the moment he touches her, she knows her heart and shields are in danger.