What is the happy ending in On Earth?

The happy ending of On Earth is: Zheng Guangming is dead.

In the story of the novel, Nan Zhou died in another country, and the strong Zheng Juan went abroad to retrieve Nan Zhou's ashes. No matter how strong Zheng Juan is, she still goes to Lacrimosa every day. Zheng Guangming knew that it was not easy for her sister to retrieve the ashes. She scattered them on the edge of Beituo Temple so that the Buddha could bless Nan Zhou. In the finale, Zheng Guangming was seriously ill and left a letter before he died. Guangming knows that he is not his own, but he has more affection for Zheng Juan than his brothers and sisters. He asked Zheng Juan to take care of himself so that he could live in this world.

Han Yulin plays Xiao Guangming:

Said she and Xiao Guangming are not Zheng's own children. Because Zheng's mother believes in Buddhism, she and Xiao Guangming should both be children found by Zheng's mother. Xiao Guangming's blindness dragged down Zheng Juan. Now he sees that his brother Bingkun and his sister have such a good relationship that they are likely to get married. Xiao Guangming took the initiative to become a monk in order to reduce the burden on his sister.