The Sister Who Stole His Heart

It was not until that fateful night that I witnessed my fiancé, Professor Edmund, embracing his "sister," Cordelia, in a passionate kiss, overhearing him declare that I was merely a "convenient arrangement," a façade to conceal their unspeakable forbidden attraction.
The engagement ring he had bestowed upon me was ill-fitted and mismatched in style—because it was never intended for me.
As for Cordelia—this seemingly innocent ward—her most closely guarded secret has finally come to light: fifteen years ago, she hastily pushed Edmund's biological sister, Violet, to her death, and subsequently usurped her identity, claiming a family and love that were never rightfully hers.