This book is on pre-order until book delivery arrives. 
 
The Mafia's Daugher (Women of the Mafia #2) by ED Crowe:
 
Capable and intelligent, Collins O’Brien was the obedient, favorite daughter of the deceased Irish mobster. Now, she’s just a woman trying to survive medical school, while hiding her weekly Saturday night adventures. After all, she’s not as perfect as she appears.

When the notorious Capo of the Bruno family, sends a marriage contract for her on the eve of her sister revealing The Games, a trio of deadly trials that determine the second-in-command of her family’s clan, she has to think fast. With no other choice, she claims to be engaged already to Hayes Monticello, her sister’s best friend.

Arrogant, hot and possessive, Hayes, the bane of her existence, has been her bodyguard since she was a kid—and is completely off limits. But right now, he’s her only hope.

Together, they agree to a tenuous deal—he’ll pretend to be the perfect fiancé, if she’ll help him win the Games. Once he’s Second, he can stop the contract and their relationship will end.

But when childish irritation gives way to forbidden passion, will the engagement remain fake? Or will their love be drowned by the incoming storm of deception and betrayal as Hayes’ dark past comes to light. And endangers them both.