Kitsune ni Yomeiri

To ensure the prosperity of her clan, Fujino will be be sacrificed to a youkai when she reaches the age of 17. Her step-mother and step-sister have always treated her cruelly. But one day, her brother, the only person she could trust, brings her a marriage proposal to a human, instead of being sacrificed to the youkai, and Fujino's destiny is changed.... This is a story of a tenuous love story spun between a sacrificial girl and a youkai.

(Source: Mag Garden, translated)