Sorry if I am repeating myself here... slowly but surely, I lose control of my own blog; I'm not quite sure whether I wrote about this before.
I think it makes sense to see beliefs as being composed of two parts: there's an objective, factual part, and there's the subjective, emotional side.
When we talk about beliefs, and especially when we are trying to change them (i.e., do "self-help"), those two parts are really two radically different beasts. It is good practice to keep them apart as best you can; because different approaches are needed for each of them. Different questions make sense.
Let's use an example, one that might be straight out of an NLP textbook: "I am very bad with women."
For simplicity, I'll take on the role of the coachee here.
NLP tends to deny it, but there is, of course, an objective part here: There are other guys out there who get laid way more than me. It may well be that I never ever approach a woman, and if I do, I get rejected in the worst possible ways.
Those are facts. It makes no sense to deny them. When you watch me at a pub, you'll see me staring at 'em nervously, and you'll see them roll their eyes in disgust when I try to talk to them. Maybe I should take a shower once in a while or stop boozing myself into oblivion.
So, the question "Is this true?" makes sense for the objective part. Trying to wish it away will probably not get me anywhere. The power of positive thinking won't change it. Complicated NLP patterns will not turn me into a seductive superhero pickup artist over night. If I have not gotten laid in five years, the factual truth of not getting laid is out there, and no master NLP practitioner will be able to talk it into nonexistence. A shower might work wonders, though.
And then there is the other part. The subjective part. My emotional reactions. With regard to those, it makes little sense to ask whether they are "true" or not. Emotions just are. With regard to the emotional part of a belief, I think that there are two practices that make sense.
One practice arises out of the question, "Where do I want to put my focus?" There was this one woman, way back, who didn't completely ignore me. Maybe she even wanted my friendship. Heck, thinking about it, maybe I even find that she found me somewhat attractive. And there was that one night when she repeatedly talked about having to leave because she needed to get up early, but then she ended up staying till the next morning and calling in sick, just so she could spend more time with me... So it might feel good to remind myself of that from time to time. Next thing I know, I might realize that a random woman on the street keeps smiling at me. And over time, it may change my attitude, and ultimately, my beliefs.
The second one is the good old buddhist practice of empathy. Learning to be more empathic toward myself. Developing empathy towards my own feelings of self-loathing and inadequacy. Realizing, ever so slowly, that all other humans suffer from the same issue. Gaining more stability and "discomfort tolerance", to use a little buzzword.
Forget about that neighbour. He or she will never come around. (Actually, one time, a neighbour did appear at my doorstep and asked me for help with her maths. And yes, things did ensue. What can I say, we were young and lonely. But that was definitely a once-in-a-lifetime experience. One I wouldn't want to have missed, though.) And that miraculous language pattern will never do anything for you.
Nor are there any guarantees that my little ramblings here contain any value for you.
Maybe I should give you a punchline, for better entertainment value. Frankly, I don't have one right now.