Based on Liza's feelings for Higgins and Freddy, does Pygmalion suggest that true love is possible and good, and why does Liza marry Freddy?

While gender roles is a major theme within Shaw's , true love and
romance are not, they are, it would seem, minor themes embedded mostly in Freddy's relationship
to the overall play. The more important themes that relate to Liza and Higgins are gender roles
and the idea of personal transformations in accord with ubermensch ("superman"). 
Having said that, Shaw does introduce a subplot of romantic and true love into
Pygmalion that is emphasized by Freddy's love for Liza.

In Pygmalion , Shaw has let it be known from the outset with the
two confirmed bachelors, Higgins and Pickering, that his characters will act out of consistent
accord with their natures, as Higgins points out about himself in Act V, saying "I can't
change my nature." Therefore all audience/reader hope of a miraculous change for Higgins or
for Liza--who from scene one has demonstrated strength of mind, of will, of independent
determination--is foretold as being a...