Stay in your Layne (Broken Alliances #1) by Sadie Winchester:
 
Alliances are broken and hearts stolen.

Layne O’Reilly, the strong-headed daughter of one of the city’s most respected criminal kingpins, encounters a man with a dark secret hired to do the dirty work of her family’s rival. When things don’t go as planned, she finds herself torn between loyalties and risking everything she has ever worked for.

Joey De Luca is the man who comes in when even the criminals don't want to get their hands dirty. Captivated by the powder keg of a woman he was hired to dispose of, he goes against one of the city’s most revered men just for what he expects to be a one-night fling.

The dark and tumultuous relationship forming between Layne and Joey gets tested as whispers throughout the criminal underworld allude to a mysterious power play on the horizon leaving everyone on edge