Full Idea
Belief is said to 'aim at truth', in the sense that beliefs are the kind of mental states that have to be true for the mind to 'fit' the world (where our desires have the opposite 'direction of fit'; the world is supposed to fit our desires).
Gist of Idea
Our beliefs are meant to fit the world (i.e. be true), where we want the world to fit our desires
Source
Pascal Engel (Truth [2002], §2.5)
Book Reference
Engel,Pascal: 'Truth' [Acumen 2002], p.57
A Reaction
I don't think it is possible to give a plausible definition of belief without mentioning truth. Hume's account of them as thoughts with a funny feeling attached is ridiculous. Thinking is an activity, not a passive state.