1, the year of no doubt refers to forty years old, which means that you can distinguish clearly when you encounter difficulties. Because it originated from Confucius' saying, "Be determined to learn five out of ten, stand at thirty, not be confused at forty, know the destiny at fifty, listen at sixty, and act at seventy, without overstepping the bounds." Therefore, people aged 40 to 40 are called "the year of no doubt" by later generations.

2. "forty without confusion" means that when a person reaches forty, he will not be confused because of ignorance, because people of this age often have a certain grasp and understanding of life. In addition, not being confused at the age of 40 means that when people reach the age of 40, there is nothing to worry about and doubt.