“Many of the Samaritans believed” because of what the woman said. Jesus made a huge impression on her, and she, in turn, made a very positive impression of Jesus on her friends. That’s the plan: bring people to Jesus, and let people know the good things he has done for you.
They invited Jesus to stay with them (unheard of in their society). And he did (even more unheard of). You know, Jesus didn’t live by society’s rules; he lived by God’s name.
“And because of his words many more became believers.” His words were like treasures, like light in the darkness, like love to the rejected. His words were ointment for the wounded, truth for the weary, and wisdom for the cynical. His words were life, and people, no matter who they were or whatever their walk of life, could tell.
They had believed on the testimony of the woman alone, but once they met Jesus, they were both captivated and captured. Now they had a personal relationship with him, and once they met him, they stood to testify: “This man really is the Savior of the World.” Not just of the Jews, or of the educated, or the men, or the religious, or the wealthy, but of THE WORLD.