A Sydney truck driver is due to learn his fate for running a red light and killing a young woman.

David William Edward Grice, 60, is expected to be sentenced in NSW District Court on Friday after pleading guilty to dangerous driving causing death over the Caringbah collision in November 2016.

Last week, the partner of the 26-year-old pedestrian, Danielle McGrath, revealed he'd purchased a diamond ring and was planning a surprise wedding proposal when she was mowed down.

Aaron Roberts instead placed the ring on Ms McGrath's finger at her funeral two weeks later, and told the court her death had left a massive hole in his heart that he would carry for the rest of his life.

"I lost the brightest part of my day, my best friend and my future wife," Mr Roberts said in a victim impact statement last Thursday.

Grice, in an apology letter he read to the court, said he was devastated his judgment had caused damage to so many lives.

"I am grieved to the depths of my being knowing that I am responsible for taking a precious girl from you," he said.

© AAP 2018