Victoria Winner Ostwen Ouhi wa Sekai de Ichiban Erasou de Aru

Lady Victoria Winner is about to have her engagement to Prince Frederic called off. Any other noble lady would cry or lash out, but not Victoria. Instead, she decides that she will simply not allow it. Whether it be broken engagements, assassination attempts, or plots against her from the nobility, there is nothing that the great Victoria cannot overcome! Welcome to the most majestic of romcoms!

(Source: K Manga)