Two possible explanations to her statement. One, there was more to their conversation than the author recorded here, personal information we don't need to know. Two the revelation of her five husbands overwhelmed her and felt as if it was everything she had ever done. Either way she was convinced beyond conviction.
Jesus provides us with a discourse on the meaning of true worship. For those that believe that all paths lead to God any form of worship is suitable. Jesus says that one must worship the Father in Spirit and truth. What is true about worship if is not done in the Spirit (note: not in a spirit)? To be of the Spirit one must be born again. To be born again one must believe that Jesus is Son of God, the Christ. The Spirit cannot be forged or approximated or imagined any other way. It is the difference between believing in a god and believing God, that what He says and what He is and what He seeks for us to be is all we need consider. Some would say that that is simply too narrow; open minded is easy only for those who wish to remain uncommitted!
Jesus speaks of many laborers, men reaping harvest from what others had sown. The word is being sown in many fashions, the testimony of the Samaritan woman at the well, the gossip in Galilee where Jesus had earlier turned water to wine, Jesus' own testimony, the public acknowledgements of John the Baptist and his disciples. The sowers go back even further to the efforts of the prophets and of old. When God is truly behind something important to Himself as this, the means and methods of planting and harvesting cannot be limited to human terms. Neither should we limit God in our minds in our day in what He is doing all around us in the harvest fields.
If I were to ask nearly any non-believer 'what is God?' the near unanimous reply would be "God is love". If I were to ask then 'what is love?' I would receive a multitude of varying replies mostly having something to do with tolerance for their sins. The question then to ask is 'doesn't that mean that love is whatever one wants/needs it to be?' or better 'that God is whomever we want/need Him to be?'. What kind of god can we ourselves make up? Is your wife whomever you wish her to be? Is your son? Is there any other working relationship that you know of that is determined by what you wish it to be? Are we not individual? Do we not have structure and backbone, interests and opinions and needs of our own that you yourself have to accept navigate and familiarize your self with? Isn't that the beauty of relationships? Why should it be any different with God? We love God because he first loved us. It was not our minute and varying personal perceptions of God with which He loved us, it was His gigantic eternal design for present and future, a love that would redeem us from our sins and set us aright into eternity. It was not our selfish 'I need you to be this' love or 'do this now for me or else' love or 'if you even exist' love for His love came before our love. What then is love? God is love? What is God? Creator and perfecter and possessor of our souls in whom no darkness dwells and in that He is absolute love.