Hannah McGuire had the right to leave Lachlan Young after months of abusive and controlling behaviour, crown prosecutor Kristie Churchill told the Victorian Supreme Court on Tuesday.
Instead of accepting the relationship was over, Young murdered the 23-year-old woman because he could not stand to see her living a life without him.
"He attacked and killed Ms McGuire in her own home," Ms Churchill said.
"Her final moments must have been filled with terror."
Young, 23, initially denied he murdered Ms McGuire, arguing her April 2024 death was a spontaneous incident.
But after eight days of evidence at trial, he admitted he strangled her 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 in Scarsdale 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
Young's barrister Glenn Casement conceded the actions after the murder were callous, but argued they were amateurish and a sign of his immaturity.
Ms Churchill rejected that submission on Tuesday.
"It cannot simply be explained by his youth or lack of education," she told the court.
"They are the actions of someone who is cold, calculated and remorseless."
She pointed to the grief of Ms McGuire's family, friends and colleagues, noting Young had also robbed them of the chance to say a proper goodbye.
"He disregarded her dignity while also eradicating any evidence," Ms Churchill said.
"He engaged in a series of acts to avoid responsibility and attempted to lay the blame of Hannah McGuire's death at her own feet."
The prosecutor outlined the concerning rates of family violence in Victoria, stating such crimes warranted significant condemnation and punishment.
She outlined the abuse Ms McGuire experienced in the lead up to her death and the fact there was an active intervention order in place at the time.
Ms Churchill called on Justice James Elliott to impose a lengthy prison sentence, arguing Young's moral culpability was high.
"He was motivated by male entitlement, jealousy and rage," she said.
Mr Casement told the court Young's youth needed to be considered in sentencing, as well as his troubled upbringing, substance abuse issues and poor mental health.
He conceded the only evidence of remorse was his client's guilty plea and a note from Young's sister in her letter of reference.
Ms McGuire's parents Debbie and Glenn wiped away tears as Justice Elliott held a minute's silence for their daughter during the plea hearing.
Young, who was seated in the back of the Ballarat courtroom, kept his head down during the moment of reflection.
Justice Elliott did not set a day down for the sentencing hearing, instead indicating he would need some time to consider all of the material.
Young was remanded in custody.
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