Knight Devoted by R. K. Thorne

He will have to choose—his goddess or his princess.

Devoted Knight Javarin wants nothing more than to serve his goddess and his kingdom—in particular, guarding the quiet, kind Princess Iseris. She’s stolen his heart, not that anyone can ever know the truth. Orphan temple boys can’t marry royals, even if those boys grow up to be knights.
Jav is drawn to protecting Iseris from anything and everything—but especially her older brother, the crown prince, in his quest to destroy all possible rivals to the throne.
Unfortunately, Iseris has a secret—a forbidden magic, abhorred by his goddess. Punishable by death. And those sworn to carry out the goddess’s cruel punishment? The Order of the Knights Devoted.
When the crown prince orders Jav to do his duty and murder Iseris, refusing would mean turning his back on his kingdom, his beloved goddess, and the only home he’s ever known… But how can he kill the only woman he’s ever loved?