Learner's definition of BELIEF
1 a : a feeling of being sure that someone or something exists or that something is true
[singular]— often + in
— often + that
He says that he is given strength by his belief in God.
He has a strong belief in his ability to win. [=he is certain that he can win]
His family has an unshakable belief in his innocence.
It's my belief that the current policy is certain to fail. [=I believe that the current policy is certain to fail]
She bought the rug in the belief that [=because she believed that] it was a real antique, not a fake.
Many people arrived early in the mistaken/erroneous belief that [=because they mistakenly believed that] free tickets would be available.
There is a growing belief that [=an increasing number of people believe that] these policies will not succeed.
b [singular] : a feeling that something is good, right, or valuable— + in c [singular] : a feeling of trust in the worth or ability of someone— + in
There is growing belief that these policies will not succeed.
Contrary to popular belief, the economy has actually improved in recent months. [=the economy has improved although many/most people do not think that it has]
2 [count] : something that a person accepts as true or right: a strongly held opinion about something
He gets angry if anyone challenges his religious/political beliefs.
We challenged his beliefs about religion.
a system of beliefs = a belief system
3 [noncount] : the state of being accepted as true: the state of being believed
a story that is worthy of belief [=a story that deserves to be believed, a believable story]
a story that defies belief = (chiefly Brit) a story that beggars belief [=an unbelievable story]
: not capable of being believed
to the best of your belief
◊ If you say something is to the best of your belief, you mean that it agrees with what you know and believe to be true.
To the best of my belief [=(more commonly) to the best of my knowledge, as far as I know], everyone arrived on time. [=I think that everyone arrived on time, but it is possible that someone arrived late and I don't know about it]