Ah, testimony and anecdote. Pretty hard to prove, can be disproved under the right conditions.
Example homeopathy: Very hard to prove, very easy to disprove.
Example a "vision": Very hard to give independent proof as only limited people had the vision, can be hard to disprove as you didn't see the vision.
Example a "medical miracle": The event happened so it may be easy to believe. The pre and post evidence may be brought into question and therefore the miracles believability.
Example homeopathy: Very hard to prove, very easy to disprove.
Example a "vision": Very hard to give independent proof as only limited people had the vision, can be hard to disprove as you didn't see the vision.
Example a "medical miracle": The event happened so it may be easy to believe. The pre and post evidence may be brought into question and therefore the miracles believability.
Being told you're delusional does not necessarily mean you're mental.