Lord Turnbull yesterday told Sheena Watters that her unprovoked attack on Alistair Green was " an offence of the most extraordinarily violent nature."
She pounced on the 54 year-old at his home in Irvine - then later lied to police that she had found him badly hurt.
The victim was so traumatised he moved out of the house he had stayed in for 30 years.
Watters, 46, returned to the High Court in Glasgow after earlier admitting assaulting Mr Green to the danger of his life.
The judge sentenced her to be locked up for 49 months.