believe in

English

Calque of the (deprecated template usage) [etyl] Latin use of crēdō (“believe”) with in plus accusative.

believe in (third-person singular simple present believes in, present participle believing in, simple past and past participle believed in)

(transitive) To ascribe existence to.
Do you believe in God? / the Easter Bunny? / ghosts?

Since I don't believe in reincarnation, I believe that the only way to eliminate suffering is to die.
(transitive) To believe that (something) is right or desirable.
I don't believe in sex before marriage.

I don't believe in making my bed.
- 2017 June 23, "Is spokes model Cindy Margolis married or single after her divorce with Guy Starkman, Know her current affairs", Hitberry.com[1]
  The couple is one of the celebrities who believed in open relationships.
(transitive) To have confidence in the ability or power of.
I believe in you, man! You can do it!

ascribe existence to

believe that something is right or desirable

have confidence in