I do not own Naruto.
Neji truly didn't mean to be nosy. Her diary was just lying on her desk with her door opened! His curiosity got the better of him and caused him to pick up the book labeled, "Hinata," and flipped to the first page.
August 17
I had to write what happened today. Neji nii-san-
"OMG!" a voice cut Neji off from his reading. He turned and saw his younger cousin pointing a finger at him.
"Hanabi-sama! I didn't-" He go cut again.
"Last time I read her diary, Nee-san beat the daylights out of me!"
"But I didn't read anything but the date!" objected Neji, putting the diary back down.
Hanabi shook her head, "Hinata nee-san doesn't even like people touching her rather secret book." She looked at her cousin with an evil grin. "I'm going to tell her what you've done."
She turned to walk away. Neji grabbed her arm, "Wait. Don't tell her."
Hanabi shook his hand off, "I want to see what she does to you."
"If you don't tell her, I'll do anything."
"Anything?"
Neji gulped but nodded, not wanting to be on his lady's bad side.
"Well let's see," Hanabi turned towards him, "I do have a lot of chores today…"
Neji found himself taking out the trash and cleaning the chamber pot. (Toilet where a person has to dump everybody's business outside and wipe it down. So imagine respectable Neji having to carry Lord Hiashi's stuff out.) Neji fell onto his bed that night, disgusted and tired. He doubted those chores were even assigned to the daughter of the clan's head.
The next morning, Hanabi presented him with another list of chores.
"What? Aren't we done after yesterday?" Neji protested.
"I could always tell Hinata nee-sama about you-know-what," Hanabi blackmailed.
Neji snatched the list, grumbling.
After a week of suffering from Hinabi's treatment, Neji was getting fed up. So when she ordered him to buy her cosmetics, Neji put a foot down.
"I. Am. Not. Doing. This. Anymore," he said, voice rising, body trembling. With one hand, Neji grabbed Hinabi by her shirt collar and marched over to Hinata's room.
The heiress sat calmly weaving in her room. "Neji nii-san? Hanabi?"
Neji released Hanabi and dropped to a knee, "Hinata-sama, I have wronged you by touching your diary. Do whatever you like, just spare me from this child!"
"D-dairy? But I-I don't write in a d-diary!"
Neji looked up, surprised. Hanabi sat on her elder sister's bed, feet hanging. She wore a smug smile and sent the diary flying towards Neji. He caught it and found out that only the first page was written in.
"Oh!" Hinata exclaimed, "Th-that was when H-Hanabi wanted to start k-keeping track of her d-days. She b-begged me to d-do it with her, b-but I wasn't per-persistent enough to keep writing in it."
Neji inquired, "Then why was it on your desk?"
"I found it in her stuff," Hanabi answered. "Perfect bait." She walked out the door, waving behind her.
Neji looked, dumbfounded at the book in his hands. He opened it.
August 17
I had to write what happened today. Neji nii-san was training with me as usual. But this time, he smiled at me and told me that I've done well. I feel so happy from such a simple but meaningful act. He has really grown into a kind person. I'm glad to call him "nii-san."
-Hinata
"I-I do m-mean it," Hinata poked her fingers together.
Neji was shaken by the entry. He sighed, standing up. Guess he couldn't pay Hanabi back if he was to be a nice person.
"I'm sorry to have bothered you, Hinata-sama," he apologized.
"N-not at all. Wh-what happened with you a-and Hanabi?" she asked.
Neji handed Hinata her diary back. "I'd rather forget about it."