Answer:
Juliet is so decisive in her final act because Friar Laurence's advice had fortified her; she does not view death as something to be afraid of.
Step-by-step explanation:
In her last scene when she sees that Romeo has died, as she feels the deepest pain for losing her beloved husband, Juliette sees death as the perfect way to be together forever and prior in the story when she took that bottle from Friar Laurence to fake her death she receive a speech so she didn't see those hours of death as something to be afraid of, but like something that would take her to the place where she wants to be.