A belief tends to be much more universal and categorical than an understanding. When you already have a belief there's no room for a new one unless you weaken the old belief first. But in the most basic sense, a belief is any guiding principle, dictum, faith or passion that can provide meaning and direction in life. Beliefs are the prearranged, organized filter to our perceptions of the world. Beliefs are the compass and maps that guide us toward our goals and give us the surety to know we'll get there.
Belief is nothing but a state, an internal, represntation that governs behavior.
Beliefs are preformed, programmed approaches to perception that filter our communication to ourselves in a consistent manner. Most people treat a belief as if it's a thing, when really all it is is a feeling of certainty about something. Our limiting beliefs are found embedded within our Intended Outcomes. Beliefs are not necessarily based upon a logical framework of ideas. They are, instead, notoriously unresponsive to logic.