Maverick by Lora Leigh
Micah Sloane knows almost everything there is to know about Risa Clay, including the vicious betrayal she endured years ago and the distrust she's harbored ever since. The only way for the Elite Ops agent to uncover an assassin - and banish the ghosts of his own dark past - is to use Risa as bait. But nothing has prepared him for her disarming blend of innocence and sensuality, or for his overwhelming need to protect her...Risa has spent six years rebuilding her life. And now, to save it, she must pose as Micah's lover and draw a killer into the open. It's a risky plan - especially with a man as powerfully seductive as Micah. But, as their charade becomes reality, Risa realizes the greatest danger may lie in losing her heart forever.