Yeah, apparently it is supposed to break down the feelings of insecurity (like somat mentioned), and by doing so, thus break down the need to put forward the persona of strength and power, etc.

In theory, it's supposed to work on the principle that if someone can love you completely, so that not any one of your "flaws" (over which you feel insecure) matter any more, than the whole reason to feel insecure will be resolved.

It's kind of doing the opposite of what the person who brought about the narcissism in you did. The person who caused it in you used to point out all your "flaws" and amplify them, make a huge issue of them, hence the reason you become insecure, etc. What this person does is then the opposite basically, they make your "flaws" pointless and of zero value to them, which is then supposed to reverse the whole thing, I would imagine.

If it works, I don't know. That's partly because I don't think I've ever met other people who love someone else unconditionally. There's always stuff about the person that they say needs to change, etc.

That is why the traditional "you need to change this and that about yourself..." therapy also doesn't work. You're just pointing out more "flaws" for the person to feel bad about.