The Virgin’s Forbidden Lord by Kim Loraine

I promised my best friend I’d take care of his sister, but she’s got other plans for us.

I’ve known Princess Alina for most of her life. She was always just my best friend’s little sister, a tag along, a kid. But I spent the last year abroad and when I got back, things had changed. Alina is all grown up, and she knows what she wants…me.
I can’t stop thinking about her but I don’t know how to make this work. She’s too young and I’ve made a promise to her brother to keep her safe. I doubt the king meant for me to fall in love with his little sister.