Alceste
Vagabond
You keep on trying. It sometimes takes a while.
If it continues without improvement, you might consider a counselor or a psychologist.
But IMO - and even though I don't have kids myself, I speak with conviction on this point - if a person beats their child with a belt or any other weapon, they have implicitly declared that they are a failure as a parent.
Not only that, but an unimaginative coward. It takes a lot more backbone and courage to become a person who is deserving of respect than it does to beat on people who won't respect you despite your lack of merit.