Konyaku Haki Sareta Koushaku Reijou wa Reijou no Kamen wo Nugi Suteru

After being publicly dumped by her fiancé, the Crown Prince Lombard, the duke's daughter Christiana appears unshaken. Despite being educated to be a refined noblewoman and the perfect queen, she has always harbored a different dream—to become Lombard's knight. Now, with the engagement off, she finally has the chance to pursue her true calling.

(Source: Manga Up!)