Unlikely Hero by Kemmie Michaels

Erin never would have expected to fall in love. Never. Not with her past, and not with her fear. She never dated; she didn't even allow herself friendships. She didn't trust her judge-of-character skills enough to allow anyone close...until Marcus. With him, a deep connection happened in spite of the walls she'd so carefully constructed around herself. His self-confessed rage fueled much of his life, with the exception of her. For Erin, Marcus dares to make the step toward love…one with the potential to heal them both.