Inspire them.
Easier said than done. I know.
Inspiration flows not only through your words but from the consonance with your life experience. When these words and experience match, you resonate. And resonance happens when you find an echo in others.
This echo brings proximity between you and others. From proximity comes companionship. We feel walking the same path. Ultimately, all this movement leads to building a momentary tribe.
That is the moment the other will believe in what you say. When you were able to create the conditions of belonging.