Attempts by Scott's lawyers to discredit Ms Clark's evidence were rejected by Judge Alister Abadee during a hearing at Sydney's Downing Centre District Court on Thursday.
Judge Abadee told the court he accepted the pair's relationship was "punctuated by emotional abuse ... born of jealousy".
He found Scott's jealousy was fuelled by content Clark posted to her Instagram, fears she would leave him and a belief she was the reason for his troubles.
Scott, 25, who appeared in court was visibly frustrated with Judge Abadee's findings, turning at one stage and whispering to supporters - for which he was told by the judge not to interrupt.
Last year Scott was found guilty of assault occasioning actual bodily harm, common assault and intimidation. He was sentenced to a 12-month community corrections order and fined $1400.
The sentence took into account the cancellation of Scott's NRL contract after the allegations emerged in 2021, and his inability to play top level rugby league in the future.
The former Melbourne Storm and Canberra Raiders centre admits he and Clark had a "turbulent" relationship but maintains at no stage did he ever assault or threaten to kill her.
In appealing the convictions, Scott's lawyers argued among other things there were questions of reliability and inconsistencies within Clark's evidence that were not sufficiently taken into account during the trial.
Judge Abadee did find Clark had exaggerated evidence she was abused on a daily basis by Scott when they were living together at a Melbourne property along with fellow Storm players Scott Drinkwater and Brandon Smith.
However, he said he did not place "much weight" on that, due to Clark having been a young adult at the time and potentially fearful for her safety, leading her to exaggerate what had occurred.
It took Clark around two-and-a-half years from the date of the last incident before she went to police, which the court heard was partly out of concern for Scott's wellbeing.
During the original court hearing, Magistrate Daniel Covington found Scott had put his hand on Clark's neck and "launched" her over a lounge into a wall, during a 2018 incident at her parents' Sylvania home in Sydney's south.
The court heard Clark was left with grazes and an egg-sized lump on her head.
The local court also heard the pair's relationship was "on and off" in the lead-up to the assault, and that Scott had became enraged, telling Clark, "You're going to f***ing leave me. Why are you like this?"
In another incident that occurred while the pair were holidaying on the NSW south coast, the former centre "charged" at Clark after the pair got into an argument, knocking her to the ground.
Scott was also convicted of intimidating Ms Clark over the phone after the pair broke up, with the magistrate accepting he told her "f*** you, I'm going to kill you. You're such a f***ing slut", and also threatened to kill himself, before driving his vehicle into a tree.
Judge Abdee described Scott's actions as "self-pitying" and "vengeful".
"During a final act of elevated emotional abuse he made a death threat to the complainant," he said.
"A reasonable person would have felt (he) was unable to let go of the relationship and his threat was genuine."
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