From Fictiondb:

A ROMANTIC CARIBBEAN CRUISE

It was the perfect holiday from Janis Morton's demanding career as a fashion buyer, especially when she met Clive Trent, handsome heir of a famous French designer. Before she knew it, Janis found herself hoping for more than just a shipboard flirtation.

But then she discovered that to avoid an arranged marriage Clive had sworn to wed the first girl he met on the cruise--and he wanted Janis to help him carry out his threat!

Reluctantly, she agreed to participate in his deception. But there was no fooling her own heart: For Janis, the pretended passion was all too real.