Mayhem & the Mortal by Shanora Williams

After a dark sorcerer curses her sister, Zaira must find a way to save her only living relative before they die. In order for that to happen, she has to enter a deadly temple no man has ever survived to reach the Prosperity Stone.

As a mere mortal in Thelanor living amongst magic wielders and beasts who blend in with their society, it seems there’s no way she can survive such a mission.

That is until she stumbles across Thane Valkor, a mysterious, brooding man of few words. One look at Thane and not only does Zaira feel an irritatingly profound connection to him, but she comes to the realization that he is exactly the person she needs in order to save her sister’s life.