If you are asking which character says it, it's Hamlet in the play Hamlet, Act 3 Scene 1. Phrases cannot own people.
There is no tangible evidence to say what Shakespeare's favorite character was.
No Shakespeare play has a character of that name.
The poetry in 'An Sylvia' belongs to Shakespeare,
Prospero is the name of the main character in Shakespeare's play The Tempest.
The Shakespearean character Hamlet says the phrase "To be or not to be" as part of an immensely famous speech in Act 3 Scene 1 of the play Hamlet. Whether he "belongs" to the phrase is something else, and I'm not sure exactly what that means.
There is no Shakespeare play with a character called Kerenza in it- can you check that you are spelling the name properly??
William Shakepeare is mentioned in this novel because he is the main character.
Iago is a major character in Shakespeare's play Othello.
Anne Hathaway is not a character in Shakespeare's writing. She was his wife.
Judith Shakespeare was a fictional character created to show the inequality of the genders during Shakespeare's time. The character was the talented twin sister of the famous William Shakespeare but was not recognized because of her sex.
Shakespeare wrote about every possible type of character.
Rosalind is the main character in Shakespeare's play As You Like It.