Yakutatazu Seijo to Norowareta Seikishi: Omoide-zukuri de Kokuhaku shitara Kyuukon & Dekiai saremashita

Annabel is a Saint who has the power of healing "Divine Power." However, due to certain circumstances, her Divine Power has severely diminished. Having become essentially useless, Annabel is forced into a betrothal and finds herself up the creek. To make a good memory before the marriage, she confesses to a Holy Knight who happens to pass by at a flower festival where people can confess their love regardless of their social standing! Although she is satisfied with only confessing, a couple of days later, Sir Lucas, the Holy Knight, that Annabel confessed to shows up asking for her hand in marriage?! But it turns out that he has come seeking to lift the curse put on him!

(Source: Kodansha)