The woman was tried and convicted for witchcraft. You had no hand in her trial. As she is bound to the stake she still insists she's not a witch. You suppose that's what a witch would say, but its not your place to judge. You're merely the executioner.
You hold the torch to the hay at her feet and she is ignited within seconds, just like a witch would be. The woman begins writhing against her restraints as she is consumed by flame. She throws her head back and lets out a loud... moan?
Her rags have long since burned away, revealing her nude but unharmed body as the inferno swirls around her. Her skin has taken a crimson hue and her yellow eyes sparkle with delight as she pants and moans. You're stunned, she really isn't a witch! She's some kind of devil.
You are left reeling by the imperfections of your justice system as she rubs her thighs together and another orgasm rocks her body.