MTL - Revenge of the Sixth Young Lady

Wei Yuewu is the unloved daughter of the powerful Marquis Hua Yang. On her way back to the capital city to marry her fiancé, she becomes the target of a ruthless assassination led by her fiancé, Marquis Jing Yuan. With the help of the Prince of Yan State, she narrowly escapes from one disaster after another and returns to the capital. Determined to avenge her enemies and unravel the mystery surrounding her engagement with Marquis Jing Yuan as well as the death of her mother, Wei Yuewu makes a deal with the Prince of Yan State. However, just as she has triumphed over all her enemies and is about to reach the acme of her life, she deliberately destroys her own future and becomes an exile of her own… - Description from Novelupdates