"Our hearts are shattered for her and her daughter Tessa."
The associate concertmaster described Williams, who is now fighting for her life in Waikato Hospital, as "one of life's most beautiful humans".
Retired Wellington music teacher Vincent Aspey told the Herald Williams was the most talented pupil he had ever taught and relished sharing her musical passion with her children.
Aspey said his former pupil, who learned to play the violin at high school in Southland, enjoyed a special bond with her two boys and girl, proudly telling him they were now learning the violin.
Monday's deadly road crash had left him in shock and he was praying his prize pupil and her young daughter would recover from their injuries.
The former violin teacher said Williams got back into contact with him two years ago, giving a special insight into the "tremendous" relationship she had with her three children.
"She wrote to me about the kids. They were learning the violin from her and they were having a wonderful relationship."
He said Jasper and Reuben were doing particularly well on the violin.
He said the girl he knew as Bindy was his star pupil at Southland Girls' High School, passing Grade 8 with distinction.
"She was the most brilliant pupil I ever had and I taught for 26 years as an itinerant teacher.
"She was just a God-given talent."
After secondary school, Williams studied performance violin at Canterbury University before leaving to work as a professional musician in Australia.
She switched to the viola and secured work with the Sydney Symphony Orchestra before moving to Brisbane and playing in Queensland orchestras.
Aspey said he had come across a recording a few years ago he had made of Williams when she was sitting her final exam and had sent it to her parents.
That prompted her to get back in touch with her first music teacher after about 30 years and fill him in on events that had taken place since she left New Zealand.
"I hadn't heard from her for decades then I received this most wonderful letter describing her life which was absolutely special to get from Bindy," he said.
A GoFundMe page has been set up for the pair raising $12,179 in under a day, surpassing its target of $6000 within hours.
Those behind the fund described the triple fatality as heart-wrenching, saying it had caused waves of devastation across the Tasman Sea.
"A horrific car crash, while on a family holiday in New Zealand, has suddenly left Belinda and Tessa as the only surviving members of the beautiful Williams family.
"When the dust settles, Belinda and Tessa, 9, will need all the community support they can get to help them cope with life after the deaths of stepfather Stephen, Jasper, 14, and Reuben, 12, who were taken from them in an instant.
"The most painful goodbyes are the ones that are never said and never explained. Any donation will help Belinda and Tessa rebuild their lives together."
Meanwhile, the grieving family released a statement yesterday on the Waikato District Health Board website.
"The families would like to thank all the well-wishers who have sent so many messages of love and support, they are finding this a huge comfort at this very sad time."
A health board spokeswoman said Williams was now in stable condition but remained in the high-dependency unit. Tessa was in a stable condition in a ward at the same hospital.
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