The Collaborative International Dictionary of English v.0.48:

Believe \Be*lieve"\, v. i.
   1. To have a firm persuasion, esp. of the truths of religion;
      to have a persuasion approaching to certainty; to exercise
      belief or faith.
      [1913 Webster]

            Lord, I believe; help thou mine unbelief. --Mark ix.
                                                  24.
      [1913 Webster]

            With the heart man believeth unto righteousness.
                                                  --Rom. x. 10.
      [1913 Webster]

   2. To think; to suppose.
      [1913 Webster]

            I will not believe so meanly of you.  --Fielding.
      [1913 Webster]

   To believe in.
      (a) To believe that the subject of the thought (if a
          person or thing) exists, or (if an event) that it has
          occurred, or will occur; -- as, to believe in the
          resurrection of the dead. "She does not believe in
          Jupiter." --J. H. Newman.
      (b) To believe that the character, abilities, and purposes
          of a person are worthy of entire confidence; --
          especially that his promises are wholly trustworthy.
          "Let not your heart be troubled: ye believe in God,
          believe also in me." --John xiv. 1.
      (c) To believe that the qualities or effects of an action
          or state are beneficial: as, to believe in sea
          bathing, or in abstinence from alcoholic beverages.

   To believe on, to accept implicitly as an object of
      religious trust or obedience; to have faith in.
      [1913 Webster]