Ethos is trust. People believe a speaker they find credible before they believe the argument.
Aristotle said a speaker persuades in three ways. Ethos is the first: we believe people we trust. Before anyone hears your argument, they judge your character.
Why do Texans buy trucks from the dealer their dad bought from? Ethos.
In a sales pitch, ethos is your track record: 'We've done this for teams like yours.'
Practice it in Skepsis