Chen Ze was aware that Betty, along with Alisa and Lindsay, had previously gone to watch Hastur's Otherworld version of "Anohana: The Flower We Saw That Day," and they even revisited the animated version of "Anohana: The Flower We Saw That Day" afterward.
Therefore, Chen Ze did not plan on allowing Betty to spoil the story, such as revealing Menma's true wish, because it wasn't in line with his thinking. Moreover, if he did let it slip, Menma's wish might never be fulfilled.
"Let Suki Umita cry when he feels like crying." This wish of Suki Umita's mother became Menma's wish as well. Even though Menma also wanted to use this opportunity to reunite her childhood friends, Chen Ze felt that it would be better to wait and let Menma reveal her wish on her own.
Shio ramen with egg drops – Chen Ze had never heard of a customer ordering this dish before, but he knew how to make this unique dish from watching "Anohana: The Flower We Saw That Day."