While hearing voices can be a symptom of some types of mental health problems, hearing voices is actually quite a common experience and not everyone who hears voices has a mental health problem. Research estimates that around 10% of people have had an experience of hearing voices at some point in their lives.
How do I know I have schizoaffective rather than just hearing voices like the majority? Especially since I rarely hear them.
You’re delusional and you hear voices. It’s a combo deal for you. But if you have concerns, write down some questions you have and bring them to your pdoc. Maybe they can explain your diagnosis to you
10% is far from the majority. 
But how do I know I’m delusional? What if the North Korea thing is real? And my boyfriend is really the devil therefore behind some of these things?
It’s not real because Morth Korea is really hateful of those outside their country. They don’t want to bring in an outsider to rule. Your boyfriend is not evil. If you believe he is evil, you should leave him
What evidence would prove to you that North Korea doesn’t have an elaborate scheme for kidnapping you, and that your boyfriend isn’t the devil?
If you have no evidence for these beliefs, what evidence would be required to stop them?
My only evidence is a voice I heard and visions. I’m not sure what evidence I would need to stop these beliefs.
If your only evidence is a voice you heard and visions you can simply use critical reasoning to dismiss the beliefs.
How can I use critical reasoning?
Ok if you want to take time to read you can look at that link. I read it over quickly and it seems to be an OK source of information.
But basically the simple understanding of critical reasoning is to question the beliefs that you hold and apply critical thinking tools to challenge your beliefs.
So what part of critical reasoning would make me dismiss my beliefs?
How are visions and a voice not reliable? What if the visions were given by some sort of technology?
You’re trying to validate a belief by asking an implausible question.
How is the question implausible?
Do you know of any existing technology that can give you the sort of vision that you had?
No but that doesn’t mean it doesn’t exist.
That you don’t know about it doesn’t mean it doesn’t exist, but if it was a possible invention don’t you think it would be widely known to exist and that it was possible?
I’m not sure what you mean here, but isn’t it possible this technology can exist?
Again you’re asking a question that you don’t have an answer for and using that as an argument for your belief. This technology would require visions to be inserted into the mind that bypass the senses without any type of physical connection to the brain, and allows for the clear communication of information. That doesn’t exist.