In the final scene of Romeo and Juliet, how can you infer that the hate between the families stems from their love?
I assume that the question you are asking relates to the interesting relationship between hate and love that is featured in this excellent tragedy, and in particular how it relates to the final scene, where, through the death of Romeo and Juliet, the Montagues and the Capulets finally make peace. Note what the Prince says to both of these families regarding the impact of their hate:
Where be these enemies? Capulet, Montague,
See what a scourge is laid upon your hate,
That heaven finds means to kill your joys with love...
The irony of the Prince's words is clear. Through the hate of the two families and their feud, fate or "heaven" decreed that the two "joys" of these families, Romeo and Juliet, should be killed by love for one another. Capulet himself says that the death of Romeo and Juliet is a "poor sacrifice for our emnity." Love of family pride and honour is shown to have tragic and irreversible consequences that will haunt Verona and in particular the two families for many years to come.