In Fair Brighton by Elena Kincaid

Sasha Palmer, a travel writer, never stays in one place long enough to find even the possibility of love. The baggage of her family keeps her closed off from everyone, but one day, love finds her in the form of strong arms, wrapping around her, and pulling her to safety from oncoming traffic. One look at Rome, and she’s a goner.
Roman “Rome” Valentin is a killer … and a good one at that. He leads a life he detests, full of self-loathing, until the day he meets Sasha. He saves her life, and she steals the heart he didn’t know he still had—but then she vanishes.
Sasha dare not stay with Rome, for their two families have been at war for decades.

But will a chance meeting and a passionate, growing love end the bitter feud or spark a battle that destroys them all?