In chapter 26 and 27 of Divergent, Tris and Tobias (Four) went down by the chasm and had a small talk. Tobias kissed Tris two times. The next morning Tris couldn't help but smile, but after going through one of Lauren's (Dauntless born initiates instructor) fears in her fear landscape, Tris gets humiliated by Tobias and she slapped him very hard.
I wonder if Tobias was trying to help Tris or to just make fun of her. When Tris slapped Tobias, I wonder what he felt like.