It is the Vav that connects the Aleph, the Truth with the Shin, the corruption, the lie, the Sheh Kehr . The interesting point here is that the letter Vav represents man. Man was created on the sixth day. The Gematria for Vav is six. This is one of man's great downfalls.
Man can begin with the truth and end with the truth.
Man can begin with the truth and end with something less than the truth, a deception, a lie. This is what is represented in the word Shaw Vi . Man is the conduit between the truth and a lie. When the subject turns away from the truth that is the time to end the conversation. It is at that point that the Shaw Vi, the obvious falsehood, makes its appearance.