Elegant Ways of the Jin Dynasty

Xie Yaoguang transmigrates into the low-martial-arts Great Jin dynasty. From the start, she kills the heir of a marquis's household, then uses her close resemblance to him to disguise herself as a man and steal the dead young master's identity. She becomes a low-ranking Embroidered Uniform Guard officer en route to take up a post in the provinces...

The bad news: She accidentally bound herself to a Villain Acting System and is the live-in husband of a villainous princess.

The good news: She also awakens a talent for the Way of Letters.

Also known as The Embroidered Uniform Guards of Great Jin, After Binding the Villain System, I Worked My Way into Becoming a Sage, and Embroidered Uniform Guard: I Cultivate the Way of Letters and Become a Sage.

P.S. The heroine is an Embroidered Uniform Guard who cultivates immortality and becomes a sage. This story combines officialdom, political intrigue, and immortal cultivation. If that's not your thing, don't read it.