Berry's body was found in a compost heap at his Main North Rd home in January last year after Joyce walked into a Christchurch police station and confessed to killing him two weeks earlier.
"Every day you'll have to remember, when you wake up, that you brutally stole the life from a kind and humble person," she told Joyce.
"Our only hope is one day you will understand how cruel and senseless it was.
"I love Martin so much, and I know that he knew it - and nothing else matters in the end."
Berry's niece Hannah Statham said losing her uncle "was traumatic".
"My world changed forever. Never in my life did I ever imagine we would get this kind of call.
"No words can express the [hurt] this has caused. Someone chose to take my uncle away from me and that is something I can never forget and never forgive."
They spoke of Berry's fear of Joyce and they worried about his safety.
He had told family and friends he wanted to leave Joyce but he did not know how to.
Joyce had a string of convictions for assaulting Berry and had spent time in prison as a result.
When he died, Berry had a protection order in place against Joyce.
Details of the day Joyce handed herself to the police, including an almost two-hour video of her "confession" interview with detectives, were also revealed in court.
No regret or empathy - Crown blasts killer
Today Justice Eaton heard from the Crown and defence before handing down his sentence.
Prosecutor Pip Currie said Joyce had caused major and lifelong trauma for Berry's whanau.
She said aggravating features of the offending were Berry's vulnerability including his growing fear of his partner, previous violence by Joyce, and the escalating domestic violence.
"She has no empathy or no remorse at all," said Currie.
"She's more concerned about her own self-interest, her property rights and her own downfall. It's concerning the only regret relates to her own circumstances."
Joyce's lawyer Richard Peters said his client has suffered "elements of cultural and social deprivation" in her life and asked the judge to consider that and her age when determining her sentence.
Justice Eaton said it was "difficult" to reconcile Joyce's version of events given the lengths that she went to conceal her crime - and Berry's remains.
"What is regrettably clear is you are unable to show any remorse," he said.
"It's a feature of this case that your violence towards Mr Berry continued notwithstanding a number of interventions. Each of those interventions was intended to offer some protection to Mr Berry and reduce your offending against him."
Justice Eaton said while the violence was "not a one-way street" in her relationship with Berry, Joyce was "overwhelmingly the aggressor".
He acknowledged Joyce's family and their "deep sadness".
"Also just how completely senseless his death was," he said.
Pre-sentence reports prepared for the court revealed Joyce - born and raised in the UK - had a childhood punctuated by poverty, domestic violence and watching her father "beat" her mother on a regular basis.
She said Berry's death was "so very, very sad" but she did not seem to show further remorse.
Life in prison - Rena Joyce is sentenced
Justice Eaton said Joyce's actions in killing Berry and dumping him, then disposing of his belongings displayed "a high level of cruelty".
"Generally, your actions were disturbing and caused so much harm to Mr Berry's family," he said.
"I accept that this murder was not premeditated, but something sparked your rage. Your response was so extreme and has had such far-reaching consequences.
"This was the culmination of an escalating level of violence towards Mr Berry."
Justice Eaton said it was "remarkable" at trial that, after having a long time to consider her evidence, she set out to "denigrate" Berry.