I said a reader in the title. I don't know if I can answer this myself, as I'm not the kind of person who hates on something for not being good. I like virtually everything, and don't care if it's not realistic. I know for a fact that all readers won't be like me.
Normally, novels have a level of realism inside them. For example, contemporary fiction is well, contemporary, and so is crime, that's often quite real. Fantasy is often real to a degree - for example, there are peasants and lords, injustice in the realm. Sci-fi is also real to a degree, some parts believable and could actually be possible.
I just really like wandering minstrels, pretty princesses, valiant knights, strange dragons and beasts that the king and queen can slay together. I can safely say that, as a hardcore fantasy reader, I have never read a fantasy book where there are wandering minstrels, plenty of princesses and princes, valiant knights that go on treasure quests for the king, queens that defend the city, etc.
Obviously, I have took note of this and made my novel so it is not just wandering minstrels, valiant knights, and instead has plenty of peasants and injustice. I think that even for fantasy, those ideas are too unreal for a reader to like them. So...
How feasible and real does any book have to be for readers to enjoy it? Does a reader care if an author goes too far with the strange, wandering minstrels, and whatever else I said? Would it matter if I made the whole thing like what I described?
Note: I acknowledge that stack exchange doesn't like hypothetical questions. I am not actually writing this, instead I am writing something more realistic and plausible (even for fantasy). This is more a question of if I write down what I dream about every night, what would happen?