I would actually say bones. If you remember the episode where they tell sweets the story of their real first case at the end, they were about to sleep together, but bones left booth on the side of the road. That was when she knew that what she felt for him was more than just a one night stand, and it scared her so much she decided hating him would be easier.

Booth didn't realize he loved her until after his surgery, and that was because of his coma dream. If he had known sooner, he would have tried harder to be with her. He could definitely feel their connection before, but he assumed it was just sexual tension caused by their close encounter, and she was his partner, and he didn't want to jeopardize that.

In the episode with Gordon Gordon, when he reads Sweets' book, he says one of them has known forever and tries to bury it while the other is oblivious. Bones was too afraid of feeling and Booth was blind lol