Majo to Kuroneko: Kateikyoushi wo Shitara Kouman na Hime-sama ni Natsuka Remashita

Anne Doherty, known as the Singing Witch, travels the world with her familiar, the black cat Ruud. In actuality, Ruud is Anne's beloved husband, who has been cursed and transformed into a cat. The purpose of their journey is to find a way to break Ruud’s curse. Hearing that a potential cure can be found in the Kingdom of Bromelia, Anne secures a recommendation from the International Magic Association to serve as the tutor to Princess Erika, the third princess of the kingdom. However, Erika is a problem child who has driven away at least a hundred tutors before Anne… Despite Erika’s fiercely cold treatment, Anne remains unfazed, and before long, Erika begins to open her heart to her—.

(Source: Yawaspi, translated)