Tarnished Crown (The Royals, #3.5)

Two years ago, one mistake cost Gideon Royal the girl of his dreams. Since then he's become jaded and stoic, caught in a spiral that has him dealing with blackmail, heartache, and loss. When he left for college, he hoped to start over. But fate has other ideas, placing Savannah Montgomery in his path again. Savannah believes there's no coming back from Gideon's betrayal. He thinks she's wrong. Forgiveness. Hope. Redemption. Gideon has vowed to win back the only girl who owns his heart. And when a Royal makes a promise, he'll go to the ends of the earth to keep it.