People need to watch her goblin party vs tiefling and judge for themselves that she's evil. There's nothing in the game indicating that she's evil. She becomes so heartbroken, conflicted when you kill the tiefling, but she is very happy when the tiefling wins and she doesn't even know why.
My guess is that she's actually Selune Cleric who got brainwashed into serving. She has no memories, and she said Shar saved her, but what if Shar brainwashed her into thinking that it's her instead of Selune? Even when looking at approval, she doesn't like wasting time but actions that are more helpful and benign would actually give her approval than most. She's more or less neutral leaning more toward good. When you do cruel actions, she tends to disapprove.
