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

Letisha discovers she has been reborn as a character in an Otome game destined to die at 18, betrayed by her fiancé, the second prince, and lose her fiefdom. At six years old, she uses knowledge from her past life to improve her struggling territory. After aiding the faerie king, she is labeled a "saint." With the support of her father and the faerie king, she plans to use her saintly powers to uncover and confront the real enemy working against her, in an effort to avoid the tragic fate written for her.