Faith by Melissa Schroeder

This book was originally released as A Little Harmless Faith. It has been expanded with a new epilogue.

Jensen Wulf is a man who has everything he could want. Money, power, and more women than he can remember. Unfortunately, the one woman he needs is the one woman who is off limits. Nicola McCann is his personal assistant and practically runs his entire family business. Any entanglement with her would be a major mistake. He does his best to ignore his need for her, until he realizes that her needs match his own.
Once he confronts her, he proposes a fling, just while they are working on Oahu. He assumes he will be able to work her out of his system by the end of their time on Oahu.
That agreement doesn’t keep either of them from falling in love even though neither of them will admit it. When someone starts taking potshots at Wulf Industries and Nicola gets caught in the crossfire, both of them quickly learn there are worse things than admitting you are in love.
Warning: This book contains two hard-headed lovers, many nasty quips, uncovered secrets, Hawaiian scenery, a trip to Rough ‘n Ready, and scenes so hot you might need an ice cold shower when you are done.