The Requiem Of The Blooming Princess summary:

The tale follows Shuki, the third princess of the Kingdom of Tou, who endures scorn and disdain due to her familial background. In the midst of her struggles, she finds solace in the company of her childhood friend, Kouei. However, their bond is shattered when fate takes a cruel turn, forcing Shuki into an arranged marriage with the second prince of a neighboring kingdom, tearing her away from the only person who brings her joy.