The thing is, I'm not sure how they're related.. Presumptuous means that the person is brave enough (in a bad way) to say something when they're not supposed to. And yes, I understand that it's not your idea but you can't just throw words in a sentence to check if you know what they mean when you're not even using them correctly
It makes sense, you said "presumptuous means that the person is brave enough (in a bad way)" Okay, so if you are shy you couldn'y be presumptous