Romeo and Juliet; How do the events in act 3 scene 1 change the outcome of the play? and how does this reflect on the love and hate theme?

My initial thoughts of the first two acts in Romeo and Juliet are filled with hope. Despite the initial Act 1 Scene 1 fight, (which the reader is led to expect due to prologue lines 'from ancient grudge break new mutiny'). When I personally read Act 1 Scene 1, I believed that this was the fight the prologue was talking about.
From then on a reader could be mistaken for thinking Romeo and Juliet is the tale of a young, handsome, love struck young man. Possibly in love with Rosaline, but Juliet is in love with him? We can then start to guess this story will be a battle of two men for the lov…