Mexican Spanish. "Paisa" is short for "paisano".
Un hombre puro paisa is someone who is very much from wherever you are and neither of you are living where you're from. If you and your friend are from Puebla, you say of him "él es mi paisa"; if your friend is addicted to candied yams (camotes), a delicacy of Puebla, "él es puro paisa".
Sometimes "paisa" is derogatory, a country bumpkin. That will depend on context.