A promise made lightly will lead to a lack of trust. (Lao Tzu, a promise made easily is bound to lack credibility)

If you have a promise, you will pay it back; if you have a promise, the time will not be easy.( "Yuan Shi Fan")

If the people have no faith, they will not be established. ("The Analects", if a person has no credibility, he will have no place to establish himself)

If he is not sincere, he cannot move people. ("The Analects") Zhuangzi. Fisherman")

Sincerity is the way of heaven; sincerity is the way of man. ("Mencius Li Lou Shang")