Due Diligence by Rebecca Kinkade

Cass isn’t Marcus’s type. He’s definitely not her type. In fact, this unapologetically sexy analyst and this so-competent-that-it’s-hot tech founder seem to have only one thing in common: Ten years ago, they decided they absolutely hated each other. None of that bodes well for them spending the next 60 days together, alone in a conference room…
Cass never expected that Marcus, the quiet, shy guy who dropped out of college—and her life—during their freshman year would ever become a multimillionaire and tech darling. But ten years later, he’s the strikingly handsome Chief Operating Officer of Libra, the tech juggernaut that Cass’s company has offered half a billion dollars to acquire. Now, it’s Cass’s job to lead due diligence: the two-month process to review all of Libra’s records before the deal finalizes. That would be a lot simpler if Marcus weren’t so damn annoying—or attractive…or talented at whispering filthy things in her ear.
And Marcus definitely never expected that Cass, the girl who broke him a decade ago, would be the final obstacle in the most important deal of his life. He also didn’t expect to learn that underneath her prim and perfect façade, Cass Pierson has a wild, untamable streak—one that Marcus just knows how to bring out in her. It turns out they have a lot more in common than just hating each other….

Due Diligence is a full-length enemies to lovers office/workplace romance novel about two people who are more than meets the eye. With tons of dirty dialogue, witty banter, and scalding and steamy hookups, this novel has no cheating or cliffhangers. HEA always guaranteed.