His now 23-year-old victim spoke of "countless times" she has moved house because she can't settle anywhere and doesn't feel safe, as well as mental and emotional harm that runs "so deep".
"I feel like I'm alone and can't trust anyone," she said.
The victim cannot see herself in a relationship and has never had a boyfriend. "Whenever I think of guys and relationships, flashes of him ... go through my mind."
The victim has issues with studying and getting a job, as she is afraid memories of her abuse could bring on a breakdown in front of others.
"It feels like my mind has been so severely ****ed over that I don't know if things are going to get better... everything around me is moving so fast and I'm just stuck in this crappy place.
"I hate Robert for ruining my life. Memories of him and his abuse are scarred on my arms."
Another victim said she was never indecently touched by Gregory, but he would "harass" her.
She said Gregory once threatened to kill her family. When the detail was read out in court, a man in the public gallery laughed and told Gregory: "You're a ****ing w***er."
The victim said she had children and was so distrustful of people she would not even let their father look after them for a few minutes.
"Personally, I think that jail is more than [Gregory] deserves. I don't think he's sorry for what he's done."
A third person victimised by Gregory said she carved the word "fail" into her arm "as a reminder to never let my guard down again".
"I don't really live life any more, I just exist. Will things ever be okay again? Will I ever be calm?"
Throughout the court appearance, Gregory stood motionless with his head hung down.
Judge Thomas Ingram sentenced him to five years in prison.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906 (Palmerston North and Levin)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Samaritans: 0800 726 666 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.