@XXSpadeMasterXX,
Quote: what is the difference between saying, I think, I think I know, I have an opinion, Or I believe?
Belief is the psychological state in which an individual holds a proposition or premise to be true.
philosophy has traditionally defined knowledge as "justified true belief". The relationship between belief and knowledge is that a belief is knowledge if the belief is true, and if the believer has a justification (reasonable and necessarily plausible assertions/evidence/guidance) for believing it is true.
A false belief is not considered to be knowledge, even if it is sincere. A sincere believer in the flat earth theory does not know that the Earth is flat.
An opinion is a belief about matters commonly considered to be subjective, i.e., it is based on that which is less than absolutely certain,