That girl is different; was Seiji Matsunaga's first opinion of Shiharu Nakamura when he first took Akane and Aoi home from the daycare center. Even the twins think so, if their tantrums about "wanting-to-see-Shiharu-tan" were any indication, then yes they thought so too.
So the next day, he asked the girl to be their babysitter even going as far as handling her institution matters as well. And boy, was he glad that he did. He finally had the chance to sleep early and wake up refreshed in the morning.
He even noticed how the twins seems more bearable ever since Shiharu became their official babysitter. He only belatedly realized the reason why.
Shiharu was, by far, the best babysitter they've had. She even does the household chores while playing with the kids. And that was saying something. Seiji was ashamed of himself, despite everything, because Shiharu's job description was only to babysit the kids not him as well.
Seiji tries, and fails miserably, to lighten the workload of Shiharu. Though everytime he tries to do so, he only ends up making it worse for her. Even if Shiharu never complains, Seiji knows that she is having a hard time mending it for him.
Added to the fact that Shiharu was cute; she was also a good person that's why Seiji can't help but fall the oh-so cute babysitter. He honestly TRIED to NOT fall for Shiharu, but its kinda hard to do when the said girl was always doing things that makes him fall for her all the more. It was like he was saying to himself: "Screw all ethics, you love her".
It's been a torture for Seiji to hide it from Shiharu. He was so desperate about it that he even resorted to get advice from Ohikawa. Oh, how wrong that was. Because Ohikawa's advice was to just confess. Saying that there's a high chance of Shiharu liking him as well and all those crap.
But he had to admit that Shiharu was acting weird around him. Always blushing out-of-the-blue and all that. But that wasn't enough proof to just follow the bastard's advice.
But in the end, here he was, alone with Shiharu on a ferris wheel cart, about to confess. If someone can shoot him now, he might just say 'please do'. But after hearing Shiharu's reply, 'on second thought, maybe not'.