Stephen did not attempt to deny her own beauty; on the contrary she gave it the fullest scope.

There was a certain triumph in her glance as she took her last look in her mirror; a gratification of her wish to show herself in the best way possible.

It was a very charming picture which the mirror reflected.
It may be that there is a companionship in a mirror, especially to a woman; that the reflection of oneself is an emboldening presence, a personality which is better than the actuality of an unvalued stranger.
Certainly, when Stephen closed the door and stood in the wainscoted passage, which was only dimly lit by the high window at either end, her courage seemed at once to ooze away.
Probably for the first time in her life, as she left the shade of the long passage and came out on the staircase flooded with the light of the noonday sun, Stephen felt that she was a girl--'girl' standing as some sort of synonym for weakness, pretended or actual.

Fear, in whatever form or degree it may come, is a vital quality and must move.

It cannot stand at a fixed point; if it be not sent backward it must progress.
Stephen felt this, and, though her whole nature was repugnant to the task, forced herself to the effort of repression.