Demon by Oona Ryda

Raised in the foster system after her parents’ murder-suicide, nursing student Sarah Miles has learned to grow a thick skin, keep her head down, and trust no one. She survives nightly threats from her supervisor and harassment from doctors on little sleep and lots of determination—until a mortally injured biker whispers a deathbed confession in her ear.
Suddenly, there’s a target on her back.
With cartel hitmen stalking her through the hospital corridors, Sarah makes a desperate choice. She trades information for protection.
Darius “Demon” Walker cleans up the club’s messes with ruthless efficiency. Babysitting a stubborn nursing student should be simple—except Sarah Miles is anything but simple. The girl is fire wrapped in scrubs, a defiant virgin who challenges him at every turn. As enemies close in, Demon will unleash the fires of hell to keep her safe.
But the beast in him that protects her body might be the very monster that shatters her heart.