Jane's outer beauty is no doubt what got Bingley's attention, but the more time he spends with her the more chance he has to notice her lovely disposition and character. They're still in the first crush stage and whether it will deepen into something more lasting remains to be seen. As Charlotte Lucas says, we can all begin freely, and Bingley by his own admission isn't one of the most resolute people in the world. Jane, however, isn't the type to fall in and out of love, and she might be taking it seriously too early. We shall see.