He apologized with a serious face.

He acknowledged his mistake and apologized.

Please forgive my fault.

We should always remember the power of Kannon in difficult times.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

He keeps the words 'Don't hesitate to correct your mistakes when you make them' in his heart, always striving for self-improvement.