When you accept something as being true you believe it.
Sometimes belief is based on what you have seen for yourself, or on your own experience and on your own feelings (BP).
At other times your belief is based on what other people say or think. This can be because they are in a position of authority or because you could not check things for yourself.
Belief-personal (BP): This is when belief is based on your personal experience or feelings.
"I want to believe it";
"I feel it must be true";
"I have no reason to doubt it";