Friar Lawrence is a character from the play 'Romeo and Juliet', written by William Shakespeare. He is the one who tries to help the ill-fated lovers to realize their love, by planning the deceive they wanted to play on their families, he told Juliet what she had to do to fake her death and then sent Romeo a letter to explain him everything. Sadly, his letter never reached him, because the messenger is stopped by the people of the town of Mantua, because of their suspect that he comes from a house that was infected by the plague.
The Nurse
Friar John got put in quarantine and the letter never got delivered.
He was quarantined.
she says truthful things to hom that he understands
Well, that is a complicated question, because no letter like that is delivered: There was a letter to Romeo talking about the false-death plan, but it was never delivered. Friar Lawrence wrote that letter and Friar John was supposed to deliver it, but was unable to due to a quarantine. Balthasar is the one who tells Romeo that Juliet has died (although she has not... this is the false-death that she will awake from), but he just tells him; he doesn't deliver a letter.
Friar Lawrence requests a crowbar to open Juliet's tomb and a letter to write to Romeo explaining the situation with Juliet.
Friar Lawrence's rationale for collecting herbs is that they can be turned into useful potions. If you want to know his rationale for doing one of the many other things he does in the play, you need to be more specific.
it wasn't delivered because Friar John, who was supposed to deliver it was quarantined because of the plague
The letter is not delivered to Romeo because it gets wrongly intercepted by Friar Laurence's messenger. This is a conflict related to miscommunication and the consequences of a failed message delivery, which adds to the tragic events in the play.
There was a plague going around and no one was allowed to enter the city or Mantua
Friar Laurence's letter is not delivered to Romeo because Friar John was kept in quarantine since there was a plague in his house. Friar John wanted to go to Mantua himself but he couldn't. Once Friar Laurence hears this he says: "Now must I to the monument alone. Within these three hours will fair Juliet wake. She will beshrew me much that Romeo Hath had no notice of these accidents; But I will write again to Mantua, And keep her in my cell till Romeo come." His plan is to go to the tomb, get Juliet then write a second letter. But Friar Laurence's second letter is never sent to Romeo because Romeo's servant Balthazar has already told him Juliet is dead. Romeo arrives at the tomb before Friar Laurence can even write the second letter, which results in Romeo killing himself, which results in Juliet killing herself.
Friar Lawrence's special talent lies in his knowledge of herbs and potions, which he uses to concoct remedies as well as deadly poisons. He is skilled in alchemy and herbal medicine, which plays a significant role in the events of Romeo and Juliet.