While I was visiting my mother at Christmas, I happened to catch a glimpse of one of those made for TV movies (don't know what it was called) that follow a predictable plan: nice family with naughty (in this case, orphan boys who become adopted by the family at the end) children. Mom and Dad have a number of serious conversations with said difficult children about life and the errors of their ways. After a time (a few weeks) the children realize, epiphany-like, how naughty they have been and make a dramatic turnaround. They live happily ever after.
Perhaps this makes for a nice tidy two hour Hallmark Channel movie that fits a stereotyped ideal of, "if only the troublesome kids had someone to sit them down and explain things they would be fine." But, it does not bear much resemblance to real life because it does not fit with the reality of human nature and how we truly become better human beings.
Children (and adults too) who behave badly (especially if we are talking about kids older than toddlers) do so because they have developed certain bad habits. Bad habits (or, "vices") are not made instantly. They become ingrained and more set into place over a period of time. To reverse a bad habit a child must replace his vices with virtues (good habits). You cannot simply subtract a vice from a person's character without instilling a virtue as its replacement. And you cannot instill a virtue instantly through talking.
Developing good habits takes time, repetition, persistence, and good will, along with the firm, consistent and loving help of others (parents especially).
Helping a child to grow in virtue must involve much more than mere talk. Conversation is helpful. But it only has a supportive role. Talking itself does not instill virtue. The good behavior must be actually practiced and repeated. Over time, the child who develops the good habit of desiring to act well, intending to do so, willing to do so, and then in fact consistently doing so--without difficulty--has acquired a virtue.
It can be compared to sports. Take karate (which I did for a couple years as a teen; my Dad earned a black belt in Tae Kwon Do karate). Karate includes learning how to punch and kick in certain ways and learning forms--sequences of specific martial arts moves precisely choreographed in traditional, set patterns. If you want to learn to punch properly, an instructor at some point is going to have to come over and place his hands on you and show you how to move. The same goes for each position of a form. Your body has to learn how to correctly assume each stance, how to execute each kick and punch. Learning to do so takes physical practice with guidance by others until it becomes an ingrained habit that your body "knows." When you become good, you can do the forms, kicks, and punches properly and with relative ease (at least without struggling). No matter how much talent you have it cannot happen instantly or automatically. And, you can't learn karate just by an instructor describing things to you while you do nothing. You have to physically practice--you have to do karate--time and time again until you learn it and become competent at it.
Virtues, or habits of good actions, are similar. While sports skills become gradually ingrained into your body through expertly guided practice, virtues become gradually ingrained into your soul through wisely guided practice.
Imagine how silly the idea would be to think that the karate kid could become an amazing karate wiz merely by Mr. Myogi talking to him with no accompanying practice at all--no waxing, or sanding, or painting, or anything. Just talk. Ridiculous, no? Same with virtue. It is simply not how human beings work to imagine that a child (or anyone) could transform bad patterns of behavior into lasting good ones just by listening to someone else talk. This is not how a virtue becomes ingrained into the soul. It is contrary to our basic human nature.
So the next time you see one of those idealized, fantasy TV movie moments where Mrs. wonderful has a real "heart-to-heart" conversation with naughty Johnny and then, magically, Johnny becomes a good boy, roll your eyes. Life just does not work this way. Let's leave the fantasy of reform through mere conversation where it should stay--in fantasy-land.