Gilly seems to believe that because Mrs. Trotter is a larger person, it follows that she should be miserable—but Mrs. Trotter clearly isn’t miserable, given her radiant smile. Again, this reflects Gilly’s prejudices, not reality. Still, Gilly apparently reasons that because Mrs. Trotter is overweight (and thus, Gilly believes, unintelligent and ineffective as a parent), and because William Ernest is such a timid pushover, that she’ll easily be able to outsmart them both and do as she likes. This gives Gilly the illusion that she’s in control—but whether she’ll see any success remains to be seen.