To Break a Demon Curse by Madeleine Eliot (epub) King and Coven Book 2
Elara has been thoroughly taken in by the Demon King’s trickery, and she is determined not to let him back into her heart after all the lies.
But with the promise of his help rescuing her mother, Elara finds herself agreeing to a blood bargain to stay with him, learn to use her mysterious demon magic, and pretend to be his betrothed.
When the Daemon Lords issue their ultimatum for Elara to prove her loyalty, Elara will have to tread carefully between love, duty, desire, and vengeance to uphold her vow to leave the Demon King at the end of their bargain.
To Break a Demon Curse is the second book in the King and Coven series, and a spicy romantasy tale featuring forced proximity, fates mates, enemies to lovers, and fake betrothal.