Belief
Belief is assent to a proposition.
Belief in the psychological sense, is a representational mental state that takes the form of a propositional attitude. In the religious sense, "belief" refers to a part of a wider spiritual or moral foundation, generally called faith.
Belief is considered propositional in that it is an assertion, claim or expectation about reality that is presumed to be either true or false (even if this cannot be practically determined, such as a belief in the existence of a particular deity).
Historically, philosophical attempts to analyze the nature of belief have been couched in terms of judgement. Both David Hume and Immanuel Kant are both particularly well known for their analyses using this framework.