Ruthless Vows by M. James

In my world, pleasure is currency and love doesn’t exist. Until I meet him.
After having been burned by love twice, I’m fine with being on my own. And after my last heartbreak–falling for the Bratva heir who owns the club I work at–I see no point in opening myself up to that again. He’s married someone else, and I prefer my independence. Nothing will change that.
Not even the stranger who buys a night with me without realizing what it is that I really do.
After that night, I assume I’ll never see Finn O’Sullivan again. But then the handsome enforcer comes back–with a different kind of proposition for me. A job–a dangerous one, but one that will pay well enough that I can put this life behind me and start fresh. The only problem?
It means having Finn watching my back. A man who I find equal parts infuriating, charming, and capable of awakening a desire in me that I thought was long dead. And when the job he asked me to do puts me in danger?
He promised to keep me safe. And I’ve never seen a man more ruthless when it comes to keeping his vows.