In Natsume Sōseki’s novel Kokoro, the narrator tells Sensei that he wants to learn from Sensei’s past. Sensei presses him: Anata wa hontō ni majime nan desu ka. “Are you really serious?” His past, he says, has taught him to doubt people, and he doubts the narrator too. But before he dies, he wants to trust another person, even just one.
He then agrees to tell the narrator his whole past. In his testament, he gives the reason: the narrator was serious and wanted a living lesson from life itself. Sensei writes that he is now breaking open his own heart to pour its blood on the narrator’s face.