This unnamed woman was most intrigued by the fact that Jesus had revealed his knowledge of her life and lifestyle. His revelation of knowing she had numerous relationships and was now living with someone she wasn't married to, was not only convincing to her that she was in the presence of Jesus, but was the motivating factor for her to run into then nearby village telling the people, "Come see a man who told me all I ever did."
She must have caused quit a stir among the people with whom she shared that information. I am sure the people she talked to were aware of this woman's tainted history. Because of her previous bad decisions and the shame associated with them, she was fortunate to find anyone to believe the things she said.
We are not told in scripture how many people came to believe in Jesus because of her personal testimony, but some did. It's another example of Jesus using the downcast and lowly, and in this case, one of the poorest of reputations to introduce the village residents to the Messiah.
The real impact of the story for me comes when the new believers tell the woman, “We no longer believe just because of what you said; now we have heard for ourselves, and we know that this man really is the Savior of the world.” John 4:42
People did not remain the same after an encounter with Jesus. Just like this story from John 4, even those considered to be one of the worst among us, can become the influencing factor to open the eyes of others and introduce them to the Lord. The greatest outcome happens when people hear and make the choice themselves to follow him.
We can see ourselves in this story. Even a poor example in some areas of life, can be used to show Jesus to others. The news then blossoms as more and more people hear the good news and personally meet the Savior of the world.