It Wasn't Love — Denise Robins

Lois had been warned about shipboard romances, but felt herself quite immune as she set out to visit her brother in Singapore.
But Philip Sanpell seemed to be something quite different. His stunning good looks and passionate kisses made her throw caution to the wind, and before the end of the voyage her heart was irretrievably lost.
But it wasn't long before she remembered those warnings and, with bitter regret, her own heedlessness...