Many a girl of more real beauty was less popular.

People liked to talk to Miss Pierce, and many could not escape from saying more than they wished, impelled thereto by her ready sympathy.

Then her eyes were really beautiful, and she had the trimmest, dearest little figure in the world; "squeezable" was the word Watts used to describe it, and most men thought the same.
Finally, she had a pleasant way of looking into people's eyes as she talked to them, and for some reason people felt very well satisfied when she did.
It had this effect upon Peter.

As he looked down into the large gray eyes, really slate-color in their natural darkness, made the darker by the shadows of the long lashes, he entirely forgot place and circumstances; ceased to think whose turn it was to speak; even forgot to think whether he was enjoying the moment.

In short he forgot himself and, what was equally important, forgot that he was talking to a girl.
He felt and behaved as he did with men.