"One may smile, and smile, and be a villain" is from which play written by William Shakespeare?

The words "one may smile, and smile, and be a villain" are found in William Shakespeare's play "Hamlet", Act I, scene v, 105–109. These words have been spoken by Hamlet. Hamlet just had his first encounter with the ghost of his father. This is when Hamlet is told by his father that he was poisoned by his brother Claudius (the "smiling, damned villain"). Claudius had grabbed both the old king's crown and his queen—Hamlet's mother, a "pernicious woman."

Hamlet is asked to let heaven punish that crime; Hamlet's job as the king's son is to get revenge on Claudius. He can be sure of the fact that there is at least one true villain in Denmark. He knows that Claudius, who is gregarious and smiling, not to mention really eager to get Hamlet's approval about his rule, is a heartless villain.

Hamlet can't trust anyone! The people who come to him with smiles on their faces could all be villains. In the play, the above quote takes on added meaning. Hamlet's old friends, Rosencrantz and Guildenstern, come to him with smiles. They are working in collusion with his uncle, the man that Hamlet knowns as evil and very corrupt.