Answer and Explanation:
At the opening of Act II, we can see Polonio trying to manipulate Reynaldo. That's because he asks Reynaldo to investigate Laertes, ask people about him and spread many lies about Laertes, the worst possible lies. He says that if people believe the lies, it is because Laertes is a truly bad person, but what he really wants is to end Laertes' reputation.
This shows how treacherous and sneaky he is that he has no good intentions and that he cannot be trusted.