"He wouldn't take no for an answer": This is what it's like to be stalked.

Bonnie* had been single for four years when he came along. Well-educated, wealthy, the son of a diplomat, he took the Sydney woman out on dates, plied her with expensive dinners; gave a perfect audition for the role of “nice boyfriend”.

“Because I hadn’t dated anyone for a while I had pretty low self-esteem,” the 34-year-old told Mamamia.

“So while I wasn’t really into him when I first met him, I thought, ‘I’ll give it a go. I haven’t really met anyone else.'”

But things soon changed.

What started as flattery became unnerving persistence, then Bonnie started catching him in weird lies. By the time they’d been together for a year, everything crumbled.

“He’d been cheating on me, seeing other people, and harassing other people,” she said.

“So when I finally found that out, I broke up with him. But he wouldn’t take no for an answer.”

In the seven months that followed, Bonnie endured constant harassment at home, at work, online – it was oppressive, inescapable.

"I had dodgy friends say they'd 'take care of him' for me, and I was seriously considering it," she said.

"I know that sounds really harsh, but the psychological effects on me were really bad. I threw myself into work, but I lost a lot of weight.

"I was suicidal at one stage because I thought I couldn't do any better and thought this was as good as it would get for me in my life. I was at rock bottom."

The barrage of phone calls and text messages - up to 20 a night - escalated to the man waiting outside her office, turning up where she shopped for groceries, sending strange gifts to her parents, and even delivering her messages to her sister in which he threatened to kill himself.

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"The worst thing was, I had a couple of friends say, 'Aren't you flattered that someone's so obsessed with you?' I had two people say that to me," she said. "That was really tough."

It's an experience that, sadly, will resonate with millions of Australians.

According to new data released by the Australian Bureau of Statistics, one in five Australian women have experienced stalking during their lifetime.

That's 1.6 million women, subjected to protracted and unsolicited behaviour by, in the majority of cases, someone they know.

Overwhelmingly - 94.5 per cent of the time - that perpetrator was male. But men are also victims; according to the ABS, there are 663,800 of them, which equates to one in every 13 men. Their stalkers are equally likely to be male or female.

As noted by the ABS, methods of stalking vary (as do legal definitions state to state), but generally victims report being watched, followed, having personal property damaged, being sent/given offensive material, or being telephoned, sent mail or contacted electronically in a way that has harmed or frightened them.

Yet only 47 per cent of women stalked by men perceived themselves to be victims of a crime, and only 37 per cent reported the most recent episode to police.

Bonnie was among them, but wasn't prepared to subject herself to a trial, to relive the nightmare with the man at the centre of it sitting in the same courtroom. Thankfully a cease-and-desist notice from her lawyer was enough to put a stop to his behaviour.

But the damage doesn't disappear that easily.

According to the ABS, in the majority - 56 per cent - of cases involving a male stalker and female victim, the stalking lasted less than six months. However, for 62 per cent of those women, the fear and anxiety persisted in the 12 months that followed.

For Bonnie, even three years on, that means difficulty trusting people and suspicion of those who seem "too interested" in her, that means she's on edge every time she walks home alone, that the sound of her phone ringing still makes her heart race.

"I am always second-guessing people," she said. "Just trust. It's really hard to trust people again."