"What's wrong, Kino?
You're staring blankly..."
Hermes asked the girl, who'd some time ago opened her shirt and was rubbing her own breasts, with a questioning voice."Ah... Yes, you know, Hermes, my breasts are steadily getting bigger, so I started thinking, 'I wonder what I should do, if I end up having an extraordinary figure'.
If that happens, it might interfere with handling Persuader, so if I become the focus of attention during my journey, won't things turn out to become quite troubling?""No, that's not what I meant.""That worry is kinyuu!"
Hermes screwed up that word. Incoming pun."...kyonyuu?"
Here we go. "kyonyuu" (巨乳) means "huge breasts"."Kiyuu...?"
And the last part: kiyuu (杞憂) means "unfounded", so he meant to say: "That worry is unfounded!""That's it!"