"As it so happens, her presence was requested at a banquet tonight, so she has no choice but to spend the day preparing for it." Sen brings up a hand to hide her mouth and giggles. "Your friend Nagakura-san is far from the only person who finds her to be quite fetching, after all."

Suspicious? Maybe. Either that or Kimigiku just has to work, which Sen doesn't mind because having her there means she'll know immediately if anything of importance happens at said banquet. If it leaves her to do her shopping alone, so be it; it just means that she'll be more free to buy less-than-healthy snacks if she so desires.

"Are you worried about me having to carry everything? If it will make you feel better about it, you may accompany me. I wouldn't mind the assistance of such a charming young man." If he's going to be following her anyway she might as well profit off it somehow, is what she's saying.