Akuyaku Reijou desu ga Shibou Flag Kaihi no Tame ni Seijo ni Natte Kenryoku wo Koushi Shiyou to Omoimasu

One day, Letisha realized that she had been reincarnated as a "villainess" (6 years old) who was doomed to die in an otome game. According to the game's plot, she will be condemned by her fiancé, the second prince, at the age of 18, and even her fiefdom will be taken over, in the worst possible outcome. To start, she saves her poor territory with her knowledge from her previous life, and when she plays a big role in helping the faerie king, she is called a "saint"...? Then, she will use the power of a saint to "lure" the true villain who tried to bring her down! Under the protection of her doting father and the faerie king, she will do everything in her power to avoid the death flag!

(Source: Starts Shuppan, translated)