Albert Barnes Commentary John 4:17

"The woman answered and said unto him, I have no husband. Jesus saith unto her, Thou saidst well, I have no husband:" — John 4:17 (ASV)

I have no husband. This was said, evidently, to evade the subject. Perhaps she feared that if she came there with the man that she lived with, the truth might be exposed. It is not improbable that by this time she began to suspect that Jesus was a prophet.

You have well said. You have said the truth.