straighten someone out
phrasal verb with straighten verb uk/ˈstreɪ.tən/ us/ˈstreɪ.ən/
informal
使（某人）改邪归正，使（某人）端正行为
to improve someone's behaviour
I thought that once he got a girlfriend that would straighten him out. 我认为他一旦有了女朋友就会迷途知返的。