A very important symbol that comes towards the end of the story is actually the mirror that Gurov sees himself reflected in just as he is about to "make a joke" to Anna, having decided that their relationship must end. Of course interestingly, what he sees in the mirror changes his view as he sees himself for who he really is for the first time and then is able to see his relationship for what it represents. The reflection that Gurov sees in the mirror causes him to realise that, for the first time in his life, he has fallen in love. Note how the text describes this epiphany to us:
His hair was already beginning to turn grey. it struck him as strange that he should have aged so much in the last few years, have lost so much of his looks. The shoulders on which his hands lay were warm and quivering. He felt a pity for this life, still so warm and exquisite, but probably soon to fade and drrop like his own. Why did she love him so? Women had always believed him different from what he really was, had loved in him not himself but the man their imagination pictured him, a man they had sought for eagerly all their lives. And afterwards when they discovered their mistake, they went on loving him just the same... Time had passed, he had met one woman after another, become intimate with each, parted with each, but had never loved. There had been all sorts of things between them, but never love.
Thus we can see that the mirror becomes a symbol of self-understanding in the short story. Literally, Gurov sees himself, but symbolically, the vision of himself triggers an important epiphany that moves beyond his physical appearance to how he has led his life and his interactions with others. Seeing himself for who he really is moves him from treating Anna like just another casual seduction to realising that he was in love with her "properly, thoroughly," and that this was the first time in his life that he had experienced this.