Revenge of the Heart by Barbara Cartland

Warren Wood is handsome, loyal and devoted to Magnolia. However, the one thing he lacks is a title and Magnolia betrays him in a heartbeat for the opportunity to be engaged to the Marquis of Buckwood.
For beautiful and beguiling as she is, behind her perfect exterior lies a scheming manipulative personality that is desperate for wealth and standing in Society.
Distraught and vowing to eschew love for evermore, Warren seeks solace in the African jungle, determined to forget the woman whose lovely face has nearly driven him to madness.
But now the wheel of fate has turned and suddenly a legacy is calling him home to take up responsibilities he never dreamt would be his, and the chance to be reunited with Magnolia who surprisingly begs his forgiveness.
Determined not to answer her siren's call, he leaves for England taking with him the sweet but mysterious Nadia, another young person desperate to leave behind the past. Together they concoct a charade that should free Warren from Magnolia's clutches and offer Nadia a new life.
As the time for Warren to meet Magnolia again grows closer, he begins to feel nervous. Will he be able to resist the seductive charms of the woman he once loved to distraction? For above all else Magnolia is determined to marry well and she is not going to let a little thing like Warren's heart stand in her way.