His Substitute Wife (Stand-In Brides, 1)

A Convenient Marriage 

Blake Latherop needs a wife in order to keep his business, and his betrothed has apparently eloped with another man. So when his fiancée's sister, Audrey Prescott, steps off the train in Whisper Creek offering to be his bride, he's in no position to refuse. But it's hardly the marriage he had in mind. 

Audrey knows she shouldn't have answered Blake's letters in her sister's name…but she couldn't bring herself to tell him of his fiancée's betrayal. Now the only way to fix things is through a temporary marriage. But as she comes to love her new life in the West, Audrey dreads the day Blake finds another solution to their situation. Because what started as a marriage of convenience has become so much more for her…