Denka, Anata ga Suteta Onna ga Honmono no Seijo desu

In a small country on a certain continent, Lamberth, there is a being known as a "Saint" who possesses strong healing powers and brings prosperity to the country. Irene, the daughter of a marquis who was engaged to Maynard, the first prince of Lamberth, is suddenly informed by Maynard that he is breaking off their engagement. The previous Saint has died, and it is necessary to decide on the next Saint as soon as possible. The two were originally engaged for political reasons, but Irene is irritated by Maynard's cold attitude. However, at the Saint selection ceremony, Irene is chosen as the true Saint...

(Source: Natalie, translated)