To Bloom in the Shadows - Grimm Retellings, #1

On Renee's twenty-first birthday, she's finally released from her tower to meet her betrothed. However, joining two kingdoms won't be as simple as jumping into a pre-arranged wedding. Sebastian's mother, Queen Gothel of Everautumn, demands the two find true love or the betrothal is canceled. She has given them mere months to fall in love and prove to her people that a human is fit to rule beside the heir.
Now, between a scorned lover from Sebastian's past, senators hungry for power, and assassins hiding in the shadows, they have their work cut out for them in this dark retelling of Grimm's Rapunzel.