Naughty Good Girl by Sapphire Knight

Adam has always been forbidden.
As my father’s close friend and business partner, there’s an unspoken rule he’s too old for me. I’m a good girl, never breaking any rules, so I’ve kept my feelings to myself.
However, circumstances change, and the grumpy billionaire I’ve grown to secretively love doesn’t hold back. All it takes is one small incident to make the tension between us snap, and I quickly discover I have a naughty side after all.
Mixed up in a world full of debts and lust, I’m traded to another man for payment and shaken to my core. I refuse to be a damsel in distress, but when my limits are pushed, there’s only one man willing to risk it all.
Adam.