A Witch's Tale — Karolyn Cairns

Madeline Farrand was condemned to burn for witchcraft when her spells go awry. A novice witch, she struggles to learn her craft on her own when her mentor dies. Sir Gavin de Mortaine swaggers to her rescue and stops her execution. Intent only on seducing his flame-haired enchantress, he refuses to believe she is really a witch. Unable to deny the reward he demands of her because of a strict code of witches, Madeline agrees to a fortnight as his companion at the coronation festivities for James Stuart.
Sir Gavin only seeks a pretty distraction during the tournament. His valiant struggle to right past wrongs ignites a desire in Madeline to be seen as a real knight's lady. She uses her spells and magic to bind Gavin to her, realizing painfully all he professes to feel for her can't be real. She vows to help him win the tournament and reclaim his birthright, even if it means he will marry another.
Madeline soon learns her magic can only create more mischief as her spells backfire with disastrous and often hilarious results. She finds herself in a disturbing position when she decides to spy on Gavin's rival, Sir Rohan de Warren. With the worst reputation in the tournament, Rohan is nothing like he is thought. Madeline is shocked to find herself drawn to him. Despite her loyalty to Gavin, she starts to gain real admiration for Rohan. His dark eyes taunt her claims to love Gavin. Rohan has never lost at anything. Driven and ambitious, the knight has no intention of losing the tourney, even when his sponsor demands it of him with his scheming and plotting. Rohan sees a prize far greater than a title and rich estates.Soon the prize worth winning becomes his rival's redheaded companion. Madeline learns through a twist of fate the greatest magic of all comes from the heart in this glittering tale of pageantry, chivalry, and witchcraft.