This is a eight-character idiom. Zhuangzi's "Zhuangzi Fisherman": "The true person is sincere, not refined but sincere, and can't move."
Sincere people are sincere, and insincere people can't touch others.
Extended data:
Sincerity: Sincerity, sincerity. With "sincerity adds up, the stone opens."
Other sources:
1, Wang Hanchong's "On Balance and Feeling Deficiency": "Honesty is a stone." ?
2. Ming Ling Mengchu's "Surprise at the First Moment" Volume 9: "Sincerity, stone opening, heart not sleepy, harmony after death."
People's sincerity can move the world and split the stone. My love for you has always been unwavering, and we will be reunited after death.
3. "Biography of Wang Jing of Guangling Temple in the Later Han Dynasty": "Cheng Jia, Shi Kai."
People's sincerity can move the world and split the stone.