Joh 4:24  "God is spirit, and those who worship him must worship in spirit and truth." 

God is Spirit and worship towards God is about spiritual renewal and connection, connecting soul and spirit with the Spirit of God. He is Absolute Love.

This is what the woman believed and was searching for, a depth of spiritual connection and true, pure love. Not being used or abused but with a true faith and hope in one who really love her from their heart not from what she could give.

Joh 4:25  "The woman said to him, "I know that Messiah is coming (he who is called Christ). When he comes, he will tell us all things." 

Jesus was what she had been waiting for, He loved her without strings. It didn't matter that she was lost, not pure in race or perfect as a person. He loved out of His own heart, character and Spirit. She could sense it too, and He said; I Am, He. I AM the Messiah. I Am Yahweh.
The disciples came back and they were amazed at the truly loving interaction. They didn't speak a word about to either Jesus or he woman. 

Joh 4:26 - 27 "Jesus said to her, "I who speak to you am he."  Just then his disciples came back. They marveled that he was talking with a woman, but no one said, "What do you seek?" or, "Why are you talking with her?" 

It is amazing after seeking water she left her water jar there. "She had found something much more satisfying and rewarding- the very presence of the loving God. He had captured her hearts attention and affection. 
She was just like a young girl finding a most precious gift and wanting to share the find with all. 
She said to everyone as she went to the town; "You've got to come and see, He knows all about everything. I believe He is the promised Messiah."
They came out to see for themselves what she was so excited about. 

Joh 4:28 -30  "So the woman left her water jar and went away into town and said to the people,  "Come, see a man who told me all that I ever did. Can this be the Christ?" They went out of the town and were coming to him." 

Jesus was filled and fulfilled also. He gained strength and found sustenance in sharing Himself with others, in opening up the love that came from the relationship He shared with The Father, God. It overflowed into and through Him by the Holy Spirit. This is God's Character love overlowing abounding in mercy, grace and lovingkindness.
The disciples now needed to prepare for harvesting what God had caused to grow. 

Joh 4:31 -38  "Meanwhile the disciples were urging him, saying, "Rabbi, eat."  But he said to them, "I have food to eat that you do not know about." So the disciples said to one another, "Has anyone brought him something to eat?" Jesus said to them, "My food is to do the will of him who sent me and to accomplish his work. Do you not say, 'There are yet four months, then comes the harvest'? Look, I tell you, lift up your eyes, and see that the fields are white for harvest. Already the one who reaps is receiving wages and gathering fruit for eternal life, so that sower and reaper may rejoice together. For here the saying holds true, 'One sows and another reaps.' I sent you to reap that for which you did not labor. Others have labored, and you have entered into their labor." 

So the people of Samaria were coming out learning and seeing Jesus and there was a great harvest of belief. They loved the presence of Jesus among them. For He loved and accepted them.
When He left He began to travel to the area of His childhood home and He knew there they would not believe or accept that He was the Messiah. He was the little son of the carpenter Joseph. The Samaritans saw Him as a savior to the world, the people of Galilee would only see Him as that little boy growing up in the region. 

Joh 4:39 -43  "Many Samaritans from that town believed in him because of the woman's testimony, "He told me all that I ever did." So when the Samaritans came to him, they asked him to stay with them, and he stayed there two days.  And many more believed because of his word. They said to the woman, "It is no longer because of what you said that we believe, for we have heard for ourselves, and we know that this is indeed the Savior of the world." After the two days he departed for Galilee."