The biggest and most important example of appearance vs. reality in this play, which is one of its key themes, is through the way that Kate deliberately disguises herself as a serving maid in her simple dress and how she chooses to play along with this disguise because she discovers that Marlow is far more receptive to her when she is pretending to be a serving maid than when she is dressed as befits her social station. Note her reasoning as she explains why she is disguising herself to her maid:
But my chief aim is to take my gentleman off his guard, and like an invisible champion of romance, examine the giant's force before I offer combat.
Kate therefore is the prime example of appearances vs. reality in this play, as it is she who pretends to be what she is not in order to "conquer" Marlow and win him for herself. Ironically her appearance of being a serving maid brings forth the reality of Marlow's true self, as he is able to speak to her and realise that he loves her in a way that he never would have been able to do were she to remain in her normal clothes without disguising herself.