Beliefs are more than ideas. They are "dearly held" ideas, or else are "very feared" or "very depressing" ideas. In other words, they have "emotional valence." They are ideas directly attacted to a certain amount or type of emotion. In this sense, they are a source of emotional energy to use as fuel in heading toward our goals.
As far as your pursuit of success, you may have found the natural gift to pursue certain goals with efficiency and knowledge of simply "how to do it." You "just know," and that is intelligence.
You've made mistakes, and found balance, discipline, and fortitude in pursuing it. And that is maturity. But even with a giftedness for something, and perseverence, even then, you may have found yourself, doubting yourself.
People told you that you couldn't achieve it, help which we all need, did not arrive, and soon, you may have found yourself starting to give up on the goal or goals. That may be when you dug into yourself and discovered that you had the "wrong thinking" to achieve the thing. That part of you was actually, silently working against accomplish the thing, and that these beliefs may have come from someone other than you, like a parent or enemy.
You then either had to change what the goal is, because it was not aligned with who you are, and therefore what you even like, or else you needed to get yourself, "an attitude change" in which you "remember who you really are," and got your beliefs in yourself, and therefore the "big dream," more honest and aligned.
It is hard to achieve anything with a partner who has directly opposed beliefs about themselves, you, or the goal or goals. You believe that you can do a thing, and they do not. You believe that it is good to help save animals and they think that resources are better spent, bettering their own lives.
Beliefs are very powerful in propelling you to success, but not just in terms of the ideas contained within them. They are much more powerful than just facts or words, because beliefs also contain a certain quantity of emotional energy in them, too - whether positive or negative. As a result they are durable, and not easily changed, because over time, we have built up supports of them through evidence that they are correct, and the emotional energy in them, gives them a sort of psychological "weight." This effectively "locks" them to the "floor of the mind," and often causes them to "go underground," into the unconscious, still operating to limit the scope of what we even try for in life.
This causes beliefs to be a durable contributor to our success, or lack of it. They define what we think is possible or impossible, and they then limit the scope of what resources, and how much we invest them toward a goal. They also limit the scope and provide the demographics of the kind of partner who might actually benefit or distract us toward or from a goal. They deeply impact each element of the strategies that we will use toward a goal as well.
Positive and useful Beliefs are then one of the 4 Cardinal Traits of Success - Intelligence, Maturity, Beliefs and Goals - that we need to find in a lasting mate and partner.