Tsugai no Yomeiri - Giyou no Miko wa Suzaku no Toushu ni Aisareru

In the snowy village of Rokka, the Suzakunomiya family, who are descended from the fire god Suzaku, are revered, and marrying into the head of the family was considered the highest honour. Sakaeda Ginka was born into a family of shrine maidens in the village and was expected to marry into the Suzakunomiya family, but her family treated her coldly as she was judged to have no chance of marrying into the family due to her lack of beauty and good looks. On the other hand, her younger sister Akane, who is good-looking and outwardly attractive, is regarded as the best miko in the village, and people have no doubt that Akane will marry into the Suzakunomiya family. On the eve of the ceremony that would decide Akane's marriage, Ginka meets the head of the Suzakunomiya family. The moment they touch each other, an unusual sensation runs through the air between Ginka and the head of the family...!

(from mangaupdates)