When you are using ethos you are appealing to the image that you aren't no liar. If your audience looks at you and thinks, "Hey this person is a liar" then it can be said that your ethos ain't no good. The root of the word ethos is something like ἤθεα, but nobody knows how to say that anymore so we just say "ethos". The root word that I just wrote a minute ago means something like "condo" or "apartment," but that doesn't really mean anything to us anymore either, it's just something I said to sound smarter.
"Why?" you may ask "Do you want me to think you are smarter?" Ha. The answer to your query is as a good one, even better than the question. The reason I mentioned those smart facts is because you now think that I know more than I actually know. (Or do I? Ha ha LOL)
If I look smarter to you, more professionalized, than you are more likely to trust me and believe that I am not a liar. And that is ethoes in a bullet shell.
And that ain't no lie, trust me and believe you me that.