Cheng is sincerity, authenticity or integrity. The Doctrine of the Mean calls it the way of heaven, and becoming sincere the way of humanity: the fully sincere person realizes their own nature, the nature of others and of things, and assists the transforming work of heaven and earth.
Cheng
Sincerity or integrity: being wholly real, the way of heaven and the goal of self-cultivation.
Also: ch’eng, sincerity