Lachlan Young, 23, did not look at Hannah McGuire's mother Debbie as she read her statement in the Victorian Supreme Court on Monday.
"I hope every day for the rest of the accused's life, he experiences the most intense pain imaginable," Mrs McGuire said, staring down at Young.
"I will never forget and I will never forgive."
Young initially denied he murdered his former girlfriend, claiming her death in April 2024 was a spontaneous incident.
But eight days into his Supreme Court trial, he pleaded guilty to murder.
Young now admits he strangled Ms McGuire in the bathroom of their Sebastopol home about 2.30am on April 5.
He then shoved her body into the footwell of her Mitsubishi Triton, drove it to remote bushland and set the vehicle alight.
As he left the scene, Young used Ms McGuire's phone to send messages to her mother Debbie, claiming she was going to take her life.
He then transferred $2000 from Ms McGuire's bank account to her mother and $5000 to himself.
When Debbie McGuire went to Young's house in a panic, he claimed he had not seen her daughter and feigned surprise at the messages.
After he was arrested on April 7, Young told officers he would "never f***ing harm that girl".
But crown prosecutor Kristie Churchill told the court the lies and the murder followed months of controlling and abusive behaviour.
Ms McGuire had taken out intervention orders against Young and was separating from him when he killed her, Ms Churchill said.
Debbie McGuire said she would have to live with the profound grief, pain and loss for the rest of her life.
"Unlike the accused, Hannah mattered," she said.
"She was important and loved and brought to this world things no one else could."
Hannah's father Glenn McGuire told the court he could never escape his grief, knowing he was meant to protect his daughter.
"I was supposed to be there to guide her and to support her to grow into the incredible woman she was becoming," the statement read.
"Instead, I had to bury her. I had to pick out a coffin instead of a graduation or a wedding dress."
Ms McGuire's aunty Michelle Smith broke down as she confronted Young, saying her heart was shattered into pieces.
"(Young) sat at our Christmas table and received gifts from us," she told the court.
"I'm angry I treated him decently.
"I'm angry that because of him I will never spend another Christmas with Hannah, I will never be able to wish her another happy birthday."
Fifteen statements were read to the court from Ms McGuire's family and friends on Monday, with Young's barrister Glenn Casement then to plead his case before Justice James Elliott
1800 RESPECT (1800 737 732)
Lifeline 13 11 14
Men's Referral Service 1300 766 491
12°C