Rutabagas are a known physical thing. Your qualification that everyone doesn't know they exist is meaningless. When people don't know of something physical, they can be told about it. They don't have to believe in it. With gods, all there is only belief in them, no knowledge at all.
If someone does not have personal experience with something (be it "material" or "immaterial") then, if they accept second (or worse) hand information regarding the existence of that thing, they
BELIEVE that that thing is "real".
If someone does not have personal experience with something (be it "material" or "immaterial") then, if they DO NOT accept second (or worse) hand information regarding the existence of that thing, they
DO NOT BELIEVE that that thing is "real".
Neither of those two conditions has the slightest bearing on whether or not that thing is "real".
You know that the sun will appear because the sun exists and has a relationship in space with the earth. No belief i required for you to know this. You know that the sun exists at night as well. We have facts that we know about the sun and earth. We don't have to believe anything about them.
I'm quite prepared to bet that the Sun will appear to rise in the East tomorrow morning (to the extent of betting the ranch on it). On the other hand, I do not totally dismiss the possibility that the Sun might "go nova" while I am sleeping and, hence, will NOT appear to rise in the East tomorrow morning (although I don't make any plans that take that possibility into account).
Not sure what gambling has to do with the difference between knowing and just believing.
See above for the difference between "knowing" and "believing". A person can "believe" in something to such a level that they will always act as if that something is "real" and (depending on what that thing is) the odds may very well favour (and to an immense degree) them in their decision based on what they "believe to be real".
I have never, personally, seen a COVID-19 virus. Based on the second-hand (and worse) information that I have received, I am prepared to
believe that the COVID-19 virus is "real" and to base my actions on that
belief.
There are many others who have, also, not personally seen a COVID-19 virus. Based on the second-hand (and worse) information that they have received (which is the same as the information that I have received), they are NOT prepared to
believe that the COVID-19 virus is "real" and they base their actions on that
belief.
Now, suppose (just for the sake of argument) that I was the ONLY person in the whole world who
believed that the COVID-19 virus was "real".
- Would that mean that the COVID-19 virus was NOT "real"?
Or, to take another example, if this were the 10th Century and I was the only person in the world who believed that women got pregnant because of the melding of small cells (that neither I nor anyone else had seen) that were contained in the ejaculate of males upon small cells (that neither I nor anyone else had seen) formed in the woman's ovaries.
- Would that mean that it was not "real" that women got pregnant because of the melding of small cells (that neither I nor anyone else had seen) that were contained in the ejaculate of males upon small cells (that neither I nor anyone else had seen) formed in the woman's ovaries?