Angela Liberatore scammed her own family into paying her for a house and land package that did not exist.
When they raised doubts, she made her cousin and husband feel like they were idiots not to pounce on the opportunity.
The couple forked out almost $400,000, believing they could trust a family member.
But Liberatore pocketed the money and, almost a decade later, they are still repaying the debt as interests rates soar.
"Trusting Angela has been the biggest mistake of my life," Jessica Lacivita told a court, between tears.
"Blood-to-blood, first cousin to first cousin, best friend to best friend, Angela looked into my eyes and lied to my face without even flinching."
Liberatore faced the County Court in Melbourne via video link from prison for a pre-sentence hearing on Wednesday.
Despite being found guilty by a jury of more than 30 fraud charges after a County Court trial in July, the 49-year-old continues to deny the offending.
In March 2014, she told Ms Lacivita and her husband Peter Koukas she was selling residential investment properties on behalf of developers and receiving commissions.
She recommended they purchase a development in Queensland, and loaned them $188,000 required to buy the land.
The couple paid her $10,000 and obtained finance from NAB to begin repaying the remainder of the debt, issuing Liberatore a $127,500 cheque from the bank.
Liberatore told them the development was due to be completed in December 2016 and allegedly produced fake emails as proof.
They paid her a further $35,000 between 2015 and 2016.
She then demanded another $200,000 from the couple for the builder to put a house on the land.
When they raised doubts, Mr Koukas said Liberatore convinced them "you're an idiot if you don't go ahead".
Liberatore helped them apply for a further loan through NAB and issued a $200,000 cheque to her business Luxury Home Designs in June 2016.
By mid-2017, Ms Lacivita started contacting her cousin for updates on the investment.
Liberatore told her it had been delayed due to cyclones in the area, and then claimed the developer had gone into liquidation, saying nothing could be done and their $388,000 investment was missing.
She told the couple not to contact her again and they reported the incident to police in October 2017.
With interest rates soaring, the couple - who now have two young children - said they are struggling to repay their debt.
"I could have secured a more promising future for my beautiful kids and instead am paying off a huge loan with absolutely nothing to show for it," Ms Lacivita said.
"My hopes and dreams of owning a house and land package has totally been crushed and now we have nothing."
She said their finances became so dire she had no choice but to pick up extra shifts as a nurse inside a COVID ward during the first wave of the pandemic.
Judge Douglas Trapnell said the offending was "very serious" and rejected her lawyer's call for a prison term in combination with community work, since Liberatore continued to deny the crimes.
"It's put the very traumatised victims through the process of a trial," he said.
He will sentence her in coming weeks.
