Nobody paid attention to what she said next?
"I envy you. But such thing is not meant to last"
Maybe she has kissed many others. In Ghost from ETM, she said if I remember well "Unsatisfied love!". I don't remember exactly what she said in Niobe but the meaning was that she is in love with Morpheus while being with Lock. Maybe she is collecting love experience! So I conclude that the sole purpose of Persephone is to collect love experience for the machines to learn.
Id go along with the emotional vampire thinking.
She is a rogue program, like the Mero, Cain/Abel, Twins etc.
She was obviously facing deletion within the Matrix, perhaps because she showed love towards the Merovingian- who i believe was booted because he betrayed his maker.
Remember in Reloaded?She claims the Mero was just like Neo once-
perhaps until the Mero turned corrupt.
She is somewhat of a lover, living a loveless existence.
Shes somewhere in limbo between good and evil, which is why she killed Cain with the silver bullet.Just to see what Mero would do...
She has more power than we think.And more history.And she will side with Trinity at Club Hel.