Adam Clarke on John 4:39

Many of the Samaritans - believed on him for the saying of the woman - This woman was the first apostle of Christ in Samaria! She went and told her fellow citizens that the Messiah was come; and gave for proof, that he had told her the most secret things she had ever done: see on Joh 4:29 (note). This word, which is twice repeated, in Joh 4:29 and here, strongly intimates that a more particular conversation had taken place, between our Lord and the Samaritan woman, than what is here related.