Clarissa is a character who is presented as being in rather a difficult space in life. She is very much engaged in the everyday realities of life, but behind this joyful exterior she profoundly questions the various decisions she has made in her life and wonders what her life is all about now. Although she is moving into middle age, it is clear that she is full of nostalgia for her youth and her love affair with Richard. However, this causes her to contrast her youth with her present, and although she finds great satisfaction in simple tasks such as buying flowers, she begins to doubt whether this is everything that life has for her and if she is somebody who is fulfilled.
This character that clearly doubts so much and struggles so much to come to terms with her own life and set of choices continues to be developed through the day that is narrated to us and the tragic death of Richard. It is importantly Clarissa out of the three heroines who is given the last word in the book as she experiences something of an epiphany and manages to forgive herself and accept herself for who she is:
Yes, Clarissa thinks, it’s time for the day to be over. We throw our parties; we abandon our families to live alone in Canada; we struggle to write books that do not change the world, despite our gifts and our unstinting efforts, our most extravagant hopes. We live our lives, do whatever we do, and then we sleep—it’s as simple and ordinary as that.
Because of the reality of life and the way that it is one long journey until we die or "sleep," all we have left is the hours, and we must enjoy each hour alone by itself in order to survive life. Clarissa's character develops precisely because she moves towards this understanding throughout the novel.