When did Ran know that JiNing had amnesia?

When we meet again. In the novel Inferiority, when Ran saw JiNing again, he realized that JiNing had lost part of his memory. In the novel "Inferiority", JiNing reported the puppy love between Ran and the conservatory of music, which had a great influence on Ran's life. Therefore, after learning that he was terminally ill, JiNing decided to do his best to make up for Ran's mistakes and atone for his sins.