I feel confused help me?

im mad and scared at the same time.I wanna beat the hell out this guy that said i talk **** about him.i keep tellin him i never talk **** about him.But he wanna belive what he wanna belive.IM mad and pissed at how iignorant he is.But then im fearful to fight him because hes a little crazy.What should i do and why do i feel this way.