Why does Vivie tell her mother at the end of the play that she is a "conventional woman at heart?"

Towards the end of the play, Vivie Warren explains her
mother Kitty's behavior in a way that shows that Vivie has a very scornful notion of
what is expected of women, and of what women are like. Her complete quote reads that her
mother:

lived
one life and believed in another…a conventional woman at
heart

This quote basically
states that, in Vivie's mind, women are meant to live lives that they really do not want
to live and that her mother's double life is a testament of just that. She is the owner
of a brothel that tries to obtain social respect by acting respectfully. Hence, she is
leading the life of a respectable lady, ironically, as she runs a
brothel.

However, Vivie is a self-repressed woman who
rejects conventionality of any kind. The normal behaviors of women are, to Vivie,
predictable, expected, and almost obligatory. This is why she, stubbornly, refuses to
act like typical women do and treat their conventionality as a weakness. However, we
know that Vivie is in constant rebellion of her mother and, although she understands her
mother's tribulation, still takes off and leaves her on her own. This clearly shows that
Vivie's overall attitude towards life is somewhat petulant, semi masochistic, and quite
silly at the same time.