Hoshi Furu Oukoku no Nina

Nina, an orphan living in Fortna Castle Town, has deep blue eyes resembling lapis lazuli, the same color as the late Princess Alisha and the God of the Stars. After being found by Prince Azure, she is made to live as a substitute princess and Priestess of the Stars. Three months later, she must become the false bride of Sett, the first prince of the neighboring nation Galgada. Despite the circumstances, Nina feels content knowing she is needed. As the characters decide to protect those they care about, their fates begin to shift.