Jesus planned to be unaccompanied for this personal encounter.  He had sent His disciples into the town to buy food while He sat down waiting for His appointment with the Samaritan woman - although she did not know that God had organised the meeting.  At mid-day, when it was very hot, the well was normally deserted.  Farmhands and animals were resting in the shade.  

But a woman from the town came to draw water from this very deep well (John 4:11).  Jesus started the conversation by asking her for a drink.  His dress and behaviour told the woman that He was a devout Jew.  That made her concerned: she knew how much such people despised Samaritans (because of their past-history of unfaithfulness to God, their compromised worship and liberal lifestyle).  That is why she asked Jesus how it was possible for Him to even talk to her, knowing that in doing so He would make Himself ceremonially unclean.  

John adds his comment that Jews did not associate with Samaritans (especially eating with them: using their cups or plates would have made them ‘unclean’).  In asking for a drink, Jesus was also asking to use her cup.  So, this conversation pointed to the paradox which is at the heart of the Gospel.  How can a holy and pure God have anything to do with polluted sinful people?  The answer is that Jesus chose to bear our sins in His own body when He died on the cross (1 Peter 2:24) and drink the cup of suffering (John 18:11) instead of us; the cup which was full of judgement for our sins (Matthew 26:39).

The wonder of the Gospel is that Jesus did not come to save the righteous but sinners (Luke 5:32, Luke 15:7).  Jesus is not concerned about where people have come from (religiously or socially) but is very concerned about where they are going.  He does not want them to go to Hell and He urges them to repent so that they can join Him in Heaven (2 Peter 3:9).  Although we may think that people are either good or bad, God sees all of us in our true light - as sinners from birth, all under His wrath until we put our trust in Jesus (John 3:36).  In a way, those who know they are bad often have a deeper hunger to be saved than those who think they are righteous.  So, we should never assume that there is anybody who cannot be saved.  The thief on the cross was saved as He trusted in Jesus (Luke 23:43).  It is right to make everybody aware that Jesus Christ has come to save sinners and those who want His salvation will come to Him and be changed by His grace.