To accept something as true or real, does not mean that you have proven, that the thing which you accept as true or real, is really true and real, you may have trusted in what you read, or trusted in what you heard, so you accept what you read or hear as truth, therefore you believe, you have faith, you have confidence, you are hopeful, you are anticipating, you have built up you expectations, but when the time has come, and the matter is revealed, you find out, that what you accepted as truth, was really false, and so your expectation perished, that is the nature of beliefs, it is two sided, true or false. It was very good that you went to the dictionary, but it is just a pity, that you did not understand that which you posted from the dictionary. Please try to understand, that we are just trying to reason, about the true meaning of beliefs, and all the other words which means the same thing as belief.
When you do not know about a matter, you will either believe it to be true or false. When you have the knowledge of a certain matter, you have no reason to believe, one way or another, because you are sure about that matter, because you know.
Hoping I was able to help you to clear your head.
Again I send many oceans of blessings and self determination to African people everywhere
ONE BLACK LOVE ONE BLACK HEART
Baba Ras Marcus.