Bound by Blood by Nikita Slater

Mine.
“You have always been worth my life. If you kill me now, I will follow you around in death as I would in life, until you decide to join me.”
Boris.
Russian mafia enforcer Boris Grekov knew the moment he set eyes on her that she would belong to him. If he had a lifetime he would spend it convincing her that they were inseparable. Unfortunately, he doesn’t have the time. Exiled from Russia for more than a decade with a bounty on his head, he must now go back to reclaim his throne. He wants his woman at his side, whether she agrees to go or not.
Laney.
Born and raised an assassin, she must complete her job or lose the one thing she holds most dear. But every time she turns around he is right there, pursuing her, touching her, making her feel after a lifetime of emptiness. She will fight him with every breath in her body, because she cannot fall in love with the man she must ultimately murder