Ikatsui Kao de Kyouaku Kishi Danchou to Osorerareru Koushaku-sama no Saigo no Konkatsu Aite wa Shakoukai no Maboroshi no Hana de Shita

Valerio is the head of a knighthood and the head of a ducal family - an impeccable title, but he has lost a series of marriage activity matches. The reason for this is a face so stern that it would make a child cry. After being rejected repeatedly, Valerio's heart breaks completely, and he chooses an aristocratic daughter, who is known as the "flower of illusion" in the social world, as his last matchmaking partner. He is sure that he will be rejected again, but when he meets her, the conversation goes smoothly and to his surprise, they get engaged! Why did this phantom flower, who was supposed to be so popular, get engaged? There seems to be a secret... Source: MU