She has no idea, of course~ That's why you need to try it on! But in an effort to move them towards the goal of Ple Two in a cute dress, she nods several times and drapes the dress over the girl's shoulder. That way, she can reach past her and quickly close off the area's webs for modesty purposes. There're a lot of weirdos in this train, you know!

With a foot or so of spare fabric, she considers herself in the mirror with a few of her eyes that aren't occupied with Ple Two. Maybe a bow..?