A Lady’s Promise by Ranee S. Clark

For orphaned New York socialite Isabella De Vries, finding a husband has become imperative. After unsuccessfully navigating four Seasons, it’s time to enlist the help of an old family friend to find her a suitable match. She trusts Preston implicitly, but his solution is both unconventional and heartbreaking: he himself will marry Isabella in name alone so that she may be the sole beneficiary of his inheritance when he succumbs to the disease that will soon take his life. His plan solves everyone’s problems: Isabella will be cared for, and his inheritance will be protected from his irresponsible younger brother, Prince.
There is no love left between Prince Baxter and his older brother. When he hears that Preston is going to marry Isabella, Prince knows he will have to charm his way into friendship with Isabella if he wants to see any portion of the inheritance money. His plot, however, quickly crumples to pieces as he and Isabella establish a genuine connection—and he makes the mistake of falling in love with her.