Itsuwari no Akujo desuga Suenagaku Shiawase ni Narimashou

It has been agreed that Lynette will marry Alfred―a man who is rumored to be a playboy and wants a young lady who can manipulate men―in place of her sister, who ran off with the dowry. In order not to be kicked out, she tries to act like the vixen Alfred wants, but he isn’t reacting the way Lynette hoped?! As it turns out, Alfred is not actually a playboy, but a pure-hearted novice in love. However, he decides to pretend to be a playboy to figure out the true intentions of Lynette, who was sent by the queen, his archenemy! *Source: K Manga*