It's not natural for children to apologize. I want to show you How you teach this important value through a book.
I remember my daughter when she understood she was wrong, she refused to apologize.
my 9-year-old son when he understands that he is wrong he cries, he's angry he runs to his room and can't handle the shame feeling.
Regret is a hard emotion.
With adults it can be the opposite:
They can say "sorry" very easily, but do they feel sorry? not always.
Do you know how to say sorry and feel those regret strong emotions at the same time?
As a children's storyteller- I tell kids stories that deal with emotions.
Through someone else's story, a child will see how it should look like.
Here is an example of a book that deals with -the full circle of sorry:
A quarrel, anger and then regret, feeling sorry and more important- understanding the truth of someone else.

Sorry! by Norbert Landa, Tim Warnes

What happens to the rabbit and the bear is exactly what happens to us in life-
They are great...