Yu Qing transmigrated into a book as the vicious female supporting character.
The original story's premise: The supporting character, Yu Qing, didn't want to marry the villain, Gu Chen, so she repeatedly tormented the heroine, Shen Yiyi, trying to steal her marriage match. In the end, Shen Yiyi killed her.
After reviewing the original plot, Yu Qing realized that the villain, Gu Chen, was rich and powerful, and died young. He was actually a pretty good choice of husband.
She couldn't understand why the original Yu Qing, a princess, would turn down such a good match and instead foolishly compete with the heroine for a poor scholar.
Fine! She'd marry the villain!
After the wedding, Gu Chen's villainous career flourished. The people suffering because of him came to beg Yu Qing to talk him out of it and keep him from courting disaster, but she refused without a second thought.
As if! She was waiting for Gu Chen to kick the bucket so she could inherit his fortune and sponsor a few poor scholars.
But who could have guessed that Gu Chen, who was supposed to die young, would defy fate, avenge himself, and ascend the throne?
On the day of his coronation, he placed the phoenix crown on Yu Qing, the princess of a fallen kingdom, with his own hands. His deep voice rang out slowly: "You are the only person in this world who understands me, Qingqing."
Yu Qing was utterly bewildered. How did she understand him? She'd just been slacking off.
Theme: Never let others tell you who I am.