Full Idea
There are three issues about belief: 1) the content which is believed, 2) the relation of the content to its 'objective' - the fact which makes it true or false, and 3) the element which is belief, as opposed to consideration or doubt or desire.
Gist of Idea
The three questions about belief are its contents, its success, and its character
Source
Bertrand Russell (On Propositions: What they are, and Meaning [1919], §III)
Book Reference
Russell,Bertrand: 'Logic and Knowledge', ed/tr. Marsh,Robert Charles [Routledge 1956], p.304
A Reaction
The correct answers to the questions (trust me) are that propositions are the contents, the relation aimed at is truth, which is a 'metaphysical ideal' of correspondence to facts, and belief itself is an indefinable feeling. See Hume, Idea 2208.
Related Idea
Idea 2208 Belief is just a particular feeling attached to ideas of objects [Hume]