Ruberia Oukoku Monogatari: Juutei no Shirinugui wo Saserareru Hame ni Natta

Erina, daughter of a duke, was raised to become the crown prince’s bride. Alvis, royal by blood but serving as a member of the Royal Guard, never imagined life beyond duty. But everything changes when Crown Prince Girard abruptly breaks off his engagement to Erina — and the king declares Alvis the new heir and Erina’s fiancé. Once a guard, now a prince, Alvis struggles to adapt to his new role and responsibilities. Erina, now engaged to a stranger, must reconcile her duty with her desire for true love. In a world ruled by status and expectation, can a love born of circumstance bloom into something real? (Source: TOKYOPOP, edited)