Transmigrate into My Fair Princess: Trapped in the Story

(Fair warning: The characters are out of character, and the plot doesn’t follow the usual drama storyline.) A childhood betrothal forces Xiao Yun to leave home alone and journey to the Forbidden City, thousands of miles away. At first, all she wants is to protect herself until the appointed time, then make her escape. But little by little, she becomes hopelessly entangled, loving someone she cannot have. In the end, she loses everything. (Tai-Yan, probably a bittersweet ending.)