Miss Wildmere's natural supposition was that he and Madge had been like brother and sister once, and that the form of the relation still existed, but that in their long separation they had grown somewhat indifferent toward each other.

She believed that the solicitude she had seen in Madge's face, on the evening so memorable in the latter's experience, was due to the jealousy of an immature, sickly girl, who had been so humored as to feel that Graydon belonged to her.

She naturally believed that if there had been anything beyond this, it would have been developed by correspondence, or else indifference on both sides would not now be so palpable.

She disliked Madge chiefly as a rival in beauty and admiration.

Nothing could be more clear than that Graydon was completely under the spell of her own fascination, and that Madge was receiving even scant fraternal regard.
All she feared was, that during the process of keep him "well in hand" he might become more conscious of Madge's attractions, which she recognized, however much she decried them openly.