belief

belief /bəˈliːf/ noun
plural beliefs
belief
/bəˈliːf/
noun
plural beliefs
Britannica Dictionary 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
[noncount]
— compare disbelief
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
2 
[count] : something that a person accepts as true or right : a strongly held opinion about something
— compare unbelief
3 
[noncount] : the state of being accepted as true : the state of being believed

beyond belief

: 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.