Polonius is sending his "man" Reynaldo to Paris to see Laertes, who is in school there. He sends him with some money to give the young man, but it seems that he has an ulterior motive. Basically, he tells Reynaldo to spy on Laertes, or at least to ask around Paris among other "Danskers" to find out if he has engaged in anything like gambling, "drinking, fencing, swearing, quarrelling" or even "drabbing" (visiting prostitutes.) Before Laertes left, his father gave him a long-winded speech warning him abut certain behaviors to avoid. Now it seems that he does not trust him to behave appropriately, and gives Reynaldo a set of equally long-winded instructions as to how to ask around about him. It is probable that Shakespeare intended this passage to develop Polonius's character a bit more by showing how duplicitous and conniving he is. It sets up his spying on Hamlet later in the play.