A Hunter Valley teacher's aide has sobbed while being given a 12-month suspended jail sentence for grooming a teenage boy for sex.

Jackie Mary Hays, 51, pleaded guilty to grooming a 15-year-old boy for unlawful sexual activity in 2015.

Ms Hays was a teacher's aide and partially blamed a weight-loss drug and unhappy marriage for her offending, which involved lewd text messages.

The boy had told police at first he was chuffed, but then things changed.

"After a while it settled in that she had a family and I kind of brushed her off a bit, I ignored her," the boy said.

Hays told police she had become infatuated with the boy, but wanted to wait until he was 16 before they had sex.

Newcastle Local Court magistrate Robert Stone said the offence had involved Ms Hays and the victim texting each other.

"Not all messages were of sexual nature, but some involved explicitly sexual talk and the offender said the messages were raunchy," Mr Stone said.

Magistrate says offender has shown remorse

In sentencing Hays to a 12-month suspended jail term, Mr Stone said while she had shown remorse, general deterrence was needed.

The magistrate says Ms Hays abused her position of trust as a school employee. ( ABC News: Colin Kerr )

"Children are to be protected from any sexual conduct even if they are willing participants," Mr Stone said.

"The aggravating factors are that the offender abused her position of trust as a school employee."

But the magistrate also noted Ms Hays had lost her marriage and her job, and had suffered denouncement in the community due to coverage in the media.

"She has shown remorse and I think her prospects for rehabilitating are good," he said.

Mr Stone recommended she continue counselling and noted there were no sex offender programs in jail for women inmates.

He said several people had provided character references.

"The general theme is that she is immensely sorry, she acted out of character and learnt from her mistakes," he said.

Magistrate notes prior good behaviour

Mr Stone said Ms Hays's prior good behaviour stood her in good stead.

"A mitigating factor is that she entered an early plea of guilty and she is of prior good character and lacked any previous convictions," he said.

But he said that prior good character had assisted Hays in getting a job at the school.

"She knew she was doing wrong things and she knew it was inappropriate," the magistrate said.

"Fortunately for the offender it is only one offence for a short period of time."

Teacher's aide claimed to be mentally ill

Ms Hays had asked to be dealt with under the Mental Health Act. ( Supplied: Facebook )

Hays had applied to have her matter dealt with under the Mental Health Act, but the magistrate rejected that application last week.

Newcastle Local Court heard Hays suffered from a borderline personality disorder.

Her solicitor also claimed the weight-loss drug Duromine may have changed her sex drive and altered her state of mind.

But Mr Stone said there was no medical link between the drug and Hays's behaviour, and the only evidence of a change in personality had come from friends who had described her as being "off the wall".

At the end of the sentencing, Ms Hays sobbed, hyperventilated, shook and rocked before she turned to the victim's mother and said sorry, then left the courtroom.