Judas is one of Jesus’ closest friends, he is one of the 12 disciples. He was the disciple Jesus trusted to take care of any money that they are given as they travelled around. Judas has an idea of what Jesus, as Messiah should be like. Jesus is not measuring up to his vision and so he agrees to betray him to the Jewish authorities. The signal to the guards is a kiss. Jesus is betrayed by the deepest sign of affection, a kiss.
Sometimes we are let down by those we love and trust the most. It is painful and leaves us lonely and distrusting. Jesus shares this experience. Christians believe that when you feel alone, Jesus is still with you.