What do you think goes through someone's mind when they keep messing up at work despite multiple warnings?

How does the unstable self-esteem of a narcissist affect their willingness to seek help or change their behavior?
How do I trust in love again after being hurt by a narcissist? I assume I’m being manipulated and how I’m behaving is somehow wrong or unlovable. I can’t fathom being accepted or truly seen. I don’t believe anyone really loves me or can.