Is she a wish troll?

TAYSHAS book #7-The Girl of Fire and Thorns by Rae Carson

Apparently this, like most of the books I've read on the TAYSHAS list, is the first book in a trilogy. This book is about Elisa. Elisa is a princess, but not thin and beautiful as Disney has programmed us to this all princesses should be. Elisa is chubby. She likes to eat and read, and doesn't see what's wrong with that. Maybe that's why I like her. Anyway, she has been married off to a handsome king from a neighboring land, in effort to secure an alliance.

Elisa has a secret. She is a bearer of a godstone. Once every hundred years, a person is born that God chooses to serve. Elisa is that person, so on her naming day, God placed a stone/jewel in her navel. Hence my question: Is she a wish troll? Haha.

Elisa is kidnapped, loses tons of weight crossing the desert, and becomes the figurehead of rebel forces. She falls in love, and leads an army.

Pretty good book, I guess.