Daughter of Light by Morgan Busse

Description: What if with one touch you could see inside the soul?

Rowen Mar finds a strange mark on her hand, and she is banished from her village as a witch. She covers the mark with a leather glove and seeks sanctuary in the White City. She lives in fear that if she touches another person, the power inside her will trigger again, a terrifying power that allows her to see the darkness inside the human heart . . .

But the mark is a summons, and those called cannot hide forever. For the salvation of her people lies within her hand.