Because he's Aki c: You can thank fan-art for that one~ [Akito doesn't mind the quiet. Tsuna seems to be doing some thinking, and thinking is generally a good thing. He hums in the pause.
Then Tsuna says that and Akito bursts into giggles. Why so aderpable Tsuna?] I dunno~ I just say what I feel. [He doesn't believe in over-thinking what he's saying]
Mm! Or, I hope so. [He doesn't like to assume things for others, but he definitely believes it. He knows it, at any rate. He'd never missed someone as much as Tsuna before]