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.
Lord, I believe; help thou mine unbelief. --Mark ix.
With the heart man believeth unto righteousness.
--Rom. x. 10.
2. To think; to suppose.
I will not believe so meanly of you. --Fielding.
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.