The Devil in the Details by Nancey Cummings

Forget serving revenge cold. Zelda wants red hot, molten lava justice. Her ex ruined her life and framed her for a robbery. Now he’s back in town, planning his next heist. To get vengeance, she’ll bargain with a charming, incredibly hot demon.
The demon’s price? Just a kiss.
This must be a trick, right? But what choice does she have?

The Devil in the Details first appeared in the Supra Velum anthology. This version has an additional scene and a new epilogue. Otherwise, the meat and potatoes of the story remains the same.