knock (some) sense in

To assist or persuade someone to start thinking sensibly (about something). Jason is convinced that he wants to get a tattoo once he turns 18, but I'm hoping we'll be able to knock sense in before then. They think they'll find success with their high school rock band, so I hope that getting booed off the stage at the talent show knocks some sense in.

knock/talk some ˈsense into somebody

(informal) try to persuade somebody to stop behaving in a stupid way, sometimes using rough or violent methods: I wish somebody would knock some sense into our politicians. ♢ Try and talk some sense into her before she makes the wrong decision.