Saved By the Lyon by Laura Landon

Only time will tell if spending her massive wealth to purchase Phillip Eversley, the Duke of Markham is the best or worst purchase Violet has ever made.

A wounded Major Phillip Eversley returns from the war to discover his father and brother are both dead and he is now the Duke of Markham. He also discovers that before their deaths, they went so deeply into debt that even if Phillip sells every unentailed property he now owns, he can never save the one property he loves most – his grandmother’s home, Parkland Estate.
Because of the massive wealth her father left her, Lady Violet Slushman becomes one of the wealthiest women in London. The former wallflower is now besieged with suitors desperate to marry her – but only for her money. She is left with no choice but to go to Mrs. Bessie Dove-Lyon, the black widow of Whitehall, renowned owner of the Lyon’s Club. Mrs. Dove-Lyon is known throughout London as the one and only person who can find a way to erase any scandal and make a match for anyone seeking one. And Violet is desperate to find a husband to protect her from the money-hungry letches. She only has two requirements, that the man Bessie Dove-Lyon chooses for her puts her wealth to good use, and he is not so handsome that he makes her plainness more obvious.