"Perhaps he'll settle down and grow some hobbit-sense"
The wizard Gandalf is always there to look after Frodo but other people thinks that Gandalf is a nuisance. This quote mean that Gandalf should take a hint and leave him alone but still he does not because when Gandalf was talking to Bilbo he said that he was going to look after Frodo, so that would mean people made assumptions based on the the actions that are done and not the facts that are given. This could also be a message that you should never make any accusation unless you know the facts.