Dansei Fushin no Moto Reijou wa, Koushoku Denka wo Tasukeru Koto ni shita.

Dansei Fushin no Moto Reijou wa, Koushoku Denka wo Tasukeru Koto ni shita. summary: "A useless person like you, who can't even use even the tiniest bit of magic, is unfit to be my, the prince's, fiancé!" The Margrave's daughter, Claire Radish, is the fiancée of the selfish and arrogant second prince, Oliver. Claire has diligently obeyed the Queen's orders and she has been busy cleaning up after her fiancée for many years. However, Oliver falls in love with the cute Baron's daughter, Carol, and declares his engagement to Claire annulled at the royal academy's graduation party...! In the midst of a series of unexpected events, the one who saves Claire is... the first prince Gilberto, who has the nickname of "Lustful Highness"?! Claire is wary of him because of his bad reputation, but...? A pure romance between a desperate young lady and a prince with a reason!