Horatio: Now cracks a noble heart. – Good night, sweet prince, And flights of angels sing thee to thy rest!
Also to know is, who says good night sweet prince?
Good night sweet prince: And flights of angels sing thee to thy rest! He is merely saying goodbye to his friend. Horatio is the only person in the play who understands Hamlet's "noble heart," so it is fitting that he is the person who sends him to heaven in eloquence.
What does sweet prince mean?
"Now cracks a noble heart. Good night sweet prince: And flights of angels sing thee to thy rest!" — Horatio, Hamlet. A common Shout-Out To Shakespeare. Just like in the original context, it's used at the death of a young man; though the variation "good night, sweet princess" is occasionally used for women.
Who says all the rest is silence?
The rest of his life is to be silence. His life ended, too soon, leaving a wide gap of silence where years of living should be. Hamlet realizes he needs to rely on Horatio to tell Fortinbras that he has Hamlet's "dying voice" for succession to the throne of Denmark.