Kahogona Wakadanna-sama no Amayakashi Kon

Io Tsuruoka is an apprentice chef at a historic inn in Asakusa. Ever since she was a little girl, she has harbored a secret crush on the inn's young heir. When rumors of his impending arranged marriage begin to circulate, Io is left heartbroken. But her despair quickly turns to shock when he suddenly proposes to her! (Source: Kodansha, translated)