The notebook given by the boy to the girl represents the meaning that the boy gives the girl a diary as a gift, which shows that he gave his heart to the other party, because keeping a diary is writing his heart. There is nothing special about the diary itself, unless the diary itself contains the contents, patterns or words of confession, which just fits the girl's careful thoughts.
What does it mean for boys to send notebooks to girls? The notebook that boys give to girls should be a blank health book, representing the love letter that boys are conquered by girls. He also hopes that a girl can write something for him. Of course, even if the girl doesn't write, he doesn't complain, as long as it helps her.
If a boy gives a girl a notebook when he leaves her, then this ... may be that the boy is interested in the girl and doesn't know what to give. As a student, she usually uses a lot of notebooks, so giving her a notebook also means "being serious".
What does it mean for a boy to send a book to a girl? It's normal for boys and girls to send things to each other. But the boy gave the girl a notebook, indicating that the boy has a good impression on the girl.
What does it mean for a boy to give a girl a book? There are generally two situations in which all boys give girls notebooks. The first is that boys give girls notebooks out of courtesy and politeness. The second is that boys send girls notebooks out of goodwill, like girls and want to close the distance between them.