Someone that pretends to be unselfish in doing
everything they do for others, but preaches against
self-serving behavior in others while actually being the most
self-serving person you ever met.
The narcissist didn't want to be obvious about who she was really
looking out for, so she spent her life
pretending to be a
beautiful person that cared about other people's best interest before her own. That would defer any suspicion people might have about her to someone else.