Dean Ward (36) met Sinead on an online dating site in May 2019 and effectively moved himself into her home in Killybegs, Co. Donegal.
Ward used lies and emotional manipulation to insinuate himself into her life, presiding judge Justice Kerida Naidoo said at sentencing on Thursday.
During the next six weeks he repeatedly attacked Ms O'Neill, spraying Mace into her face, tying her up, choking her and then raping her, threatening her with a hammer and punching her in the face.
He controlled her access to friends and family, took over her online banking and monitored her whereabouts, social media and mobile phone use and removed her contraceptive device as she slept.
Opening up about her ordeal, Sinead, who waived her anonymity so that Ward could be named publicly, told RTE’s Morning Ireland that she was first suspicious of Ward not long after they met, when she found out that he had been lying to her about where he was living.
"He came clean and said he had lied to me and that he was actually living in Dublin, which of course was another lie, but I had told him at that point, no, I didn't want him to come back, I don't know why he is lying or what's going on, but something wasn't right and I put my phone on silent.”
She said that he then sent her a flood of text messages and calls, and as a result, she turned off her phone and went to bed.
The next morning she was getting ready when Ward entered her home.
"That's when he had told me he had slept in my shed and I kind of laughed it off because it was a strange thing to do I suppose.
"But he had made a comment about a candle that I had left burning in the kitchen and he wouldn't have seen that had he not been out the back of my house, so I believed him when he said that."
She said that he tried to control her life, accessing her social media accounts and deleting them.
“He deleted everything that I was on, bar my Facebook,” she said explaining that it was because she had no phone signal at her house and it was her only way of keeping in contact with her family.
However, he monitored all her messages.
"He was tracking my phone, so any messages I was receiving or sending. At the time I wasn't able to understand it, but he was able to see them even before I had seen them and he was tracking, I think it was through Google, all my movements from the phone."
She says she was "embarrassed and ashamed" and didn’t want anyone to know what was going on.
"There were so many threats on my life that one day at work, I broke down to my boss and told her what was going on," she said, adding that if it were not for her boss, she wouldn’t be alive today.
"She completely took over. She kept getting at me every day... she kept telling me 'Sinéad you are not going to live through this, you're going to die, he is going to kill you.'"
Sinead recalled that when she wrote her original statement to Gardai she was afraid they wouldn’t believe her because it was “so out of any kind of normality.”
"It happened to me and I'm reading it and it's just too much to take in, like this can't be real," she said.
Encouraging others to speak out if they are in similar situations she said: "There are so many resources out there and there is so much help... it is being believed; it is being taken seriously."
Ms O’Neill said she is relieved that the ordeal has come to an end.
"For the past three years I pretty much locked myself away from everybody. Again, going back to being embarrassed and ashamed which is ridiculous. But also, it leaves you with a lot of paranoia and a lot of fear that wouldn't be logical to anyone else,” she said.
“Unless you have been through it, you couldn't possibly understand it.”
"There were times when I would say to myself 'Sinéad, he is in prison, he can't touch you' - but it didn't matter, it was my body reacting to the trauma."
While she said she is grateful to everyone for the support she does not believe that Ward is capable of changing and she said he showed no remorse during the trial.
"I would imagine in his mind, I caused this, I did this, which is really really scary because he is going to spend the next 17 years in prison. What is his mind going to be like when he comes out?” she said.
"And I know it's something I need to just let go of, I do understand that I have to rebuild my life and get on with things and I will. I have an awful lot of support and I know I am strong enough to do it, but that is definitely something that kind of haunts me.”
Ward formerly of Ballintlea, Hollyfort, Gorey, Wexford was jailed in 2016 for four years for falsely imprisoning and assaulting a young mother in November 2015.
Ward and that woman had met on the internet dating website Plenty of Fish and Ward attacked her on their third date in the woman's own home.
Ward, also known as Dean Alexander Fowkes, used a different name on first meeting his victim.
At a trial earlier this year, he was convicted of twelve offences; four assaults, one false imprisonment, one making a threat to kill, two counts of production of articles, three counts of rape and one count of coercive control on dates between June 11 and July 17, 2019.
The offences occurred between the woman meeting the man for the first time and his arrest by armed gardai at her home on July 17 2019. He has been in custody since his arrest.
He attempted to get away from officers but was caught jumping over a back wall.
Ward told gardai during an interview that they had a happy relationship and were planning for marriage and a baby.
If you have been affected by any of the issues raised in this article, please contact Women’s Aid on 1800 341 900, Rape Crisis Helpline on 1800 77 8888 or in an emergency situation, contact Gardai on 999.