A deal with the Elf King : a Married to magic novel

For centuries, the elves have taken young women from Luella's village to be their Human Queen. To be chosen is seen as a mark of death by the townsfolk. A mark nineteen-year-old Luella is grateful to have escaped as a girl. Instead, she's dedicated her life to studying herbology and becoming the town's only healer. That is, until the Elf King unexpectedly arrives... for her.