For me, real tolerance has two components.

The first one is that you accept that others will have differences (of opinions, beliefs, etc.) from you. And you don’t assume that those differences exist because they are deficient (they lack knowledge, they are stupid, etc.), but because they have different backgrounds than you.

The second component is the harder one and it is that you accept that others won’t accept your difference even if you accept theirs. And you assume it’s not because they have bad personalities and character (egotist, close-minded, etc.), but because they just need to train their empathy more.