How?

that's the question I ask myself at this moment,
how can someone be so thoughtless
how can someone be so careless?
how can someone be so heartless?
how can someone lie for such a long time?
how can someone like that sleep at night?
how can someone.....kill all my dreams and not even care
after telling me she does as she has never cares for anyone before?
I long to know HOW?