The Succubus’s Prize by Katee Robert

Belladonna was born wrong. At least that’s what her parents, religious community, and even her beloved sister believe. Walking away from the church hasn’t helped her come to terms with her purpose in life, and when her sister is diagnosed with cancer, Belladonna has nowhere to turn…until a demon offers her a deal.
After agreeing, nothing is like she expects. There’s no fiery hell to speak of. Her soul seems to still be her own. All she’s required to do is serve. When she’s auctioned off to Rusalka, a powerful and ruthless succubus, her confusion only grows. Rusalka surprises her at every turn, even refusing to allow Belladonna to bear a child that would benefit the entirety of their territory.
Rusalka has sacrificed everything for their people. There are no lengths they won’t go to as leader…but they see something of themself in Belladonna, a familiarity that tempts beyond anything they could have dreamed. They want to keep her.
But if Belladonna can’t release her shame and step into a future where she’s living for herself instead of in service to others… Things may be over even before they begin.