My Fiancé's Brother Is the Don

To escape being handed to a cartel as payment for her father's debts, Isabella shows up to marry Leo, the younger son of the Falcone crime family, only to catch him cheating with her stepsister. So she plays the one card her late mother left her: a secret that lets her blackmail the Falcone matriarch into announcing the engagement anyway. The night before the gala, a cold, dangerous stranger drags her into his car in a back alley, and she barely gets away. The next evening, in front of the whole city, she meets him again. He's Alexander, Leo's older brother and the Don himself. And he has no intention of letting his brother's fiancée go.