The angel of the LORD finds Hagar, while she is trying to solve her problem by herself. He sees her, and the first thing He does is to confront her about the situation of her heart. He does that with a question similar to the ones asked to Adam, and to Cain. It is not that the LORD needs the information, since He already knows. He wants Hagar to understand what is happening, and then He provides directions, and a promise of support.
The LORD finds. The LORD confronts. The LORD guides. The LORD promises. All because of who He is. All because of His character.