Reaper (Montana Bounty Hunters #1)
Delilah Devlin

However, partnering with Jamie Burke had taught him a few things. There were women who could focus on the job at hand without letting silly distractions get in the way of his concentration. Jamie was one of those rare creatures who didn’t gossip, didn’t get into his business, and could actually be useful when shit went sideways and they had to get physical. Her methods of subduing a target weren’t ones he’d ever employ, but she knew how to compensate for her smaller frame and lesser strength. Over the months since their boss, Fetch Winter, had put them together, Reaper had come to admire the woman’s grit and ingenuity.
Case in point was their present predicament..."
See what happens when Reaper has to deal with a ride-along author who, when shit goes sideways, proves his first female partner's "grit and ingenuity" weren't just lucky happenstance, and who challenges Reaper's relationship rules...