The Future King's Bride: Harlequin comics

Millie was the kind of girl to be more interested in horseback riding than romance. And she’s in a good mood today after an exhilarating ride on her favorite horse. As she’s rewarding her horse, a man calls out to her. Great, she’s being scolded again for her wild ways. But when she turns around, she sees Crown Prince Gianferro of the kingdom of Mardivino, who is staying on her family’s estate! Millie had hoped to avoid him—she’s not much for strict formalities. And now he’s gazing at her for some reason...when he’s supposed to be asking for her sister’s her hand in marriage!