Full Idea
Truth and falsehood both belong primarily to beliefs, and only derivatively to propositions and sentences.
Gist of Idea
Truth belongs to beliefs, not to propositions and sentences
Source
Bertrand Russell (My Philosophical Development [1959], Ch.15)
Book Reference
Russell,Bertrand: 'My Philosophical Development' [Routledge 1993], p.136
A Reaction
I'm not sure why a proposition which is date/place stamped ('it is raining, here and now') could not be considered a truth, even if no one believed it. Is not the proposition 'squares have four sides' true?