The falling action in "Romeo and Juliet" starts to happen in Act III, Scene ii,- after Romeo kills Tybalt. Juliet becomes confused as to what to feel because her new secret husband is now banished from Verona while her beloved cousin is dead by Romeo's hand. This strengthens the pair's assumptions that they are never to be together in a relationship approved by their families.
In order to remove some sorrow after Tybalt's death, Lord Capulet decides that Juliet needs to marry Paris immediately, which puts Juliet in a state of despair because she is already married to Romeo. The nurse basically gives up on Romeo and Juliet's relationship, siding with the idea that Juliet needs to simply marry Paris and get over Romeo.
Friar Lawrence, however, still hopes that the pair can remain together, which is why he devises a plan to make Juliet appear dead so her family does not know that she is running away with Romeo. Because of unforeseen circumstances, Romeo does not receive the message that Juliet is not really dead. He sees her "dead" body and kills himself. When Juliet awakes, she sees Romeo dead and kills herself, thus bringing both the Capulet and Montague families together at last and out of their long family feud.