noun (n)

• any cognitive content held as true(noun.cognition)

  Antonym:
  disbelief, unbelief
  

  source: wordnet30
• a vague idea in which some confidence is placed(noun.cognition)

  Example:
  It strengthened my belief in his sincerity.
  

  Synonym:
  feeling, impression, notion, opinion
  

  source: wordnet30
• Assent to a proposition or affirmation, or the acceptance of a fact, opinion, or assertion as real or true, without immediate personal knowledge; reliance upon word or testimony; partial or full assurance without positive knowledge or absolute certainty; persuasion; conviction; confidence; as, belief of a witness; the belief of our senses.(noun)

  source: webster1913