Kiss of Fire by Lilah T. Bane

I offer you a bargain. If you agree to my terms I will take you from this wretched place and give you whatever you desire.
Raya has spent the last ten years of her life on the secure ward of a hospital, blamed for the fire which killed her adoptive parents. When the doors are blown apart by a furious creature of shadows who offers to rescue her, she barely hesitates.
Shadeed is a Jinn – proud, imperious, and arrogant – and he seems to think Raya is something she’s not. He says she’s part fire fae – a supernatural being able to create flames with a mere thought. He’s clearly mistaken, but he’s offering her freedom in exchange for posing as his betrothed.
He has the face of an angel and the desires of a demon.
What red-blooded female could resist?
Shadeed needs the support of the fire fae to win the throne. An alliance with Raya will help his cause but she’s seemingly unaware of the power she possesses. He vows to help her find her true self – even if he gets burned in the process.
Because there’s something about this half-breed that sets his blood on fire.