In the opening scene of Act II, Polonius wants Reynaldo to check on Laertes's conduct by going to France, and then spreading false slanders about Laertes around the town where Laertes attends college. Polonius then tell Reynaldo that if the people around town recognize the slanders that Reynaldo has been spreading about Laertes, then that means that Laertes has been acting poorly. However, if the people around town do not recognize the slanders that Reynaldo has been spreading about Laertes, then that means that Laertes has been acting well.
