The Poison Daughter by Sheila Masterson 

To err is human. To avenge is Divine.

Every person Harlow Carrenwell kisses dies, and that’s the way she likes it. The poison-lipped youngest daughter of Lunameade’s magical founding family has used her power to annihilate their enemies.

Her first husband is in the ground. Her new betrothed is next.

But Harlow has a secret. When she’s not acting as her parents’ assassin, she moonlights as a vigilante hunting abusive men in their walled city.

Meet a man. Lure him in. Kill him with a kiss. Until one night Harlow kisses a mark and he doesn’t die.

Worse, he is her new betrothed, Henry Havenwood, and now he knows about her double life. Instead of exposing her and sparking a war between their rival families, he does something far more dangerous – he whisks her away to marry him in his wild mountain fort.

Harlow doesn’t trust Henry, but the only way to protect her family and city is to uncover what his family is planning.

Cursed with a husband she can’t kill and trapped in a fort surrounded by vampire-infested woods, Harlow must do the impossible: make the man who knows she’s a killer fall in love with her anyway.