I decided on 'trust' prompt because, well, it's my thesis topic and I found it's really interesting. Kageyama and Hinata's trust building is beyond perfect and I really want to write about it. I hope it's not gonna be too scientific but I consider that this somehow my (weird) analysis about their relationship

Disclaimer: Haikyuu! sadly isn't mine. Also, beware of really really bad grammar, English isn't my mother tongue :(

Enjoy!

Trust

The weirdest thing between Kageyama Tobio and Hinata Shouyou's relationship was their mutual trust on each other. Stranger would probably think that they were just a simple-minded dorks and a little bit slow on their feelings. Their comrades thought differently though. It was definitely 100% trust, and that 100% trust is scary. Mutual trust is scary. Well, at least for their opponent, because they couldn't break that scary combination between Hinata and Kageyama, no matter what they did.

Everybody would probably think that it's easy to trust a genius setter as Kageyama, but some of old Kageyama's friends didn't think so. Kageyama was stiff, a little bit hard too be approached, perfectionist and also demand for perfection. Not to mention his super fast tosses were hard to be caught. He would yell and ask for more. His junior high school friends couldn't keep with him. Let alone trust, they couldn't even touch Kageyama's tosses. No one wanted to catch his tosses again. No one wanted to get yelled again. So they left him without a proper communication and explanation. They were probably too afraid and Kageyama was too prideful. Kageyama was hurt and it's probably hard to trust someone again to be there to receive his fast tosses. No, until he met with a certain orange-haired guy, Hinata Shouyou.

The first time they met, they were on the other side of net, secretly admiring each other skill and ability on volleyball. Both Kageyama and Hinata probably already recognized each other's ability from the very beginning. Hinata on his physical ability to jump and run really fast while Kageyama on his perfect and fast tosses.

Both of them thought the same thing. 'I wish I—'

'As tall as him' Hinata thought.

'As fast as him' Kageyama thought.

So when they met again, this time as a team, both deep down felt a strong connection. They knew that they shared the same passion on volleyball. They knew that they both want to stand on the court to play volleyball, to spike the ball, to toss the ball, to catch the ball, to protect the ball and keep on winning. To achieve all of those dreams, both of them need each other. Probably because of this mutual understanding, mutual goal, mutual needs, mutual preference, mutual choices and mutual passion on volleyball, Hinata decided to give his all to trust his now new partner, Kageyama. Hinata Shouyou would never taken Kageyama's tosses for granted. He wanted it. He loved it. He needed it. He craved for it.

As for Kageyama, this was like a brand new chapter in his life. It's not impossible to repair trust and build a new trust. It took time, knowledge and a whole lot more proofs so that he could trust again. He surprised how easy it was for Hinata Shouyou to do all of that.

"I'm here!" Hinata shouted all of his might to show Kageyama that he would be there and ready to hit any toss that Kageyama gave to him. Hinata would say it again and again that he'll always be there. In return for Hinata 100% trust to him, Kageyama was slowly trying to trust again, to believe again, and to rely on his teammate again. All thanks to Hinata trustworthiness, secretly wondered how did he changed his life and mind.

So when Kageyama asked Hinata about why he trust him 100% while they were walking home together, all Hinata did was give a little shrug and said;

"You have an excellent ability as a setter. You have this integrity too as a volleyball player, like, c'mon, you never come late to our practice. Heck, we even do a marathon every morning while everyone's still eating their breakfast." Hinata chuckled. "It's my 99th victory by the way!" He added, beaming. Kageyama thought that he was interacting with a sun now, because Hinata's smile was ridiculously dazzling.

"Dumbass" Kageyama snorted, not really honest with his feelings.

"You were not really honest with yourself, were you, Kageyama-kun?" Hinata added a suffix behind Kageyama's name and Kageyama know that Hinata was teasing him. Kageyama was about to open his mouth and retort back but Hinata cut all of Kageyama's words with his.

"Sometimes you're a little bit mean, but you never use my weaknesses to turn against me. You still sent me those tosses and you help me with my training too. Even though you're stupid in Math and English." Hinata grinned. "It's their loss not to have you as their setter or not to trust someone like you."

Kageyama's chests tighten a bit. He knew that Hinata was really good at flattery but he could never take it well. All Kageyama needed to do now was hide his now blushing face.

"Don't say embarrassing things out loud!" was all Kageyama could manage to say.

"But you're the one who's asked!" Hinata retorted back.

Kageyama couldn't deny this one. Hinata was right. So he shut his mouth and this time they walked in silence. It was really weird for Hinata because usually he could say anything. Was he really that embarrassing? It was really weird for Kageyama because usually it was Hinata who's keep on talking, but now he's as quiet as mouse. The silence engulfed both of them except the sound of their footsteps and Hinata's crackling bike. So Kageyama decided that this time he should take the initiative first.

"—you" He let out a small voice.

Hinata could barely catch it. "What?"

"I said, thank you, dumbass!" Kageyama blushed and grabbed Hinata's head.

"Ow! Ow! I understand! It hurts, you stupid!"

Kageyama didn't release Hinata's head but instead he ruffle his hair a little bit, feeling Hinata's soft orange hair on his hands.

"Me too." I trust you.

Empirical Trivia:

To be a trustworthy person you need these three: ability, integrity and benevolence.

Guess what? Kageyama and Hinata have all of that ;)