The Faerie Handmaid by Louisa Morgan

When it's revealed that the new king of Camelud is cursed, Braithe, handmaid to the most powerful priestess in the realm must travel to the land of the fae to break the curse, but to do so Braithe must step out of her mentor's shadow and into her power, in this bewitching coming of age tale from Louisa Morgan. When Braithe was left as an acolyte on the Isle of Apples, she never dreamed she'd become handmaid to Morgana, the most powerful priestess in all of Camelud, but now she is content to live out her days in service to the Priestess. But when a powerful mage comes to Morgana and Braithe with concerns that the new king of Camelud is being cursed by powerful magic, the two must journey to the White City deep in fae country to investigate. The magical city is nothing like Braithe imagined and the fae are cold and callous toward humans and quick to bewitch. Despite the constant threat of danger, Braithe just may be the key to discovering who is cursing the king, but to do so she will have to step into her own power.