Tensei Hakushaku Reijou wa Oujisama kara Nigedashitai

Countess Sherazade of the Holy Kingdom of Florentino is hit with a flood of memories. Memories of a past life, in which her current life is just a teen love novel called, "The World that Surrounds Me," or "My World" for short. Her life is about to go from tragic to downright traumatic and she's not about to sit around and let it happen. In order to do that, she can never, ever marry the prince!

(Source: Renta!)