William Tyrrell in red shirt, sitting in chair with drinkThe woman was the former foster mother of William Tyrrell who went missing in 2014. (Supplied: NSW Police)

The former foster mother of missing boy William Tyrrell has had her conviction for assaulting and intimidating a different child overturned due to her “unique and heartbreaking stresses”.

The woman, who cannot be identified for legal reasons, successfully appealed her conviction for two counts of assault and two counts of intimidation against the child.

She was initially placed on a 12-month community corrections order, which required that a conviction be recorded against her name in March last year.

On Friday, Judge Miiko Kumar found the four offences against the 59-year-old were “proven” but determined that the sentence was “too severe” and overturned the conviction.

“The appellant [the woman] has experienced a number of traumatic events, the most being the disappearance of a child who she clearly loved,” Judge Kumar told Downing Centre District Court.

“I accept that she experienced a combination of factors, which were unique and heartbreaking stresses.

“She has been described as a blameless character, which I accept.”William Tyrrell's foster mother in a black jumper and white shirt underneath, walking with her husband outside court

The woman and her husband can’t be named for legal reasons. (ABC News)

The woman wiped away tears as she was instead ordered to serve a 12-month conditional release order.

Woman had pleaded guilty

The 59-year-old previously pleaded guilty to two assault charges after she hit the child with a wooden spoon and kicked them in the thigh in 2021.

Magistrate Susan McIntyre later found her guilty of intimidation, including by saying the child was going to “cop it” during an argument, and that they were being a “smarty pants” and would get a “slap across the face”.

Judge Kumar accepted the woman’s argument that the offences were in the “low end” of objective seriousness.

“She’s a person whose culpability on any view must be regarded as being at a low level and one, which is strongly mitigated by as powerful [of a] subjective case as could be imagined,” the judge said.

At the time the woman spoke to a friend about the pressure she was under following William’s disappearance, and Judge Kumar found she had demonstrated “genuine remorse” for the psychical assaults.

The offences arose after the home and cars of William’s former foster parents were bugged by NSW Police for about a year.

William disappeared from his foster grandmother’s house near Kendall on the Mid North Coast in 2014, aged three.

No-one has ever been charged over William’s disappearance.

The woman denies any involvement in his disappearance.