A woman who was allegedly raped and murdered by her 'narcissistic' boyfriend dreamed of 'achieving something in her life' and building a family, her grieving sister told a court.
Stephen Sexton, 39, and Joanna Derkacz, 37, had been together for three years and the relationship was welcomed by her sister who had 'treated him as family'.
But the marine engineer and father-of-one is now on trial accused of strangling Ms Derkacz, 37, to death after subjecting her to 12 months of 'controlling and coercive' behaviour.
Ms Derkacz, a recruitment consultant, was found dead at their home in Waterlooville, Hampshire on December 28, 2023.
Moments after murdering her, Sexton contacted sex workers as he became 'aroused', prosecutors said.
Sexton denies murder, rape and coercive or controlling behaviour.
Giving evidence at the trial on Monday, Ms Derkacz's sister Arleta wiped away tears as she said her sister 'wanted to achieve something in her life, to buy a house, and have a family'.
Arleta went on to tell jurors that she had a strong relationship with Sexton and believed him to be a good man but now regrets ever having thought so highly of him.
Stephen Sexton, 39, is accused of strangling recruitment consultant 37-year-old Joanna Derkacz
Moments after murdering her, Sexton contacted sex workers as he became 'aroused', prosecutors said
Ms Derkacz was found dead at their home in Waterlooville, Hampshire, in December 2023
She said: 'He was very confident. He was a good bloke, that's what I thought. I had a good relationship with Stephen, that's what I thought.'
She added her sister was 'very excited' after having met Sexton on the dating app Tinder.
Arleta, from Chichester, West Sussex, said Sexton would regularly help her own partner on renovation work at their house.
'He built a table in my beauty room. We treated him as family.'
She said she previously thought he was 'the best brother in law that I ever had'.
'I will regret saying that for the rest of my life,' she told jurors.
Arleta said there was an incident around a year before Ms Derkacz's death which led to her falling out with Sexton.
Speaking emotionally from the witness box, Arleta said: 'I hate him. I treated him as family but I started having these feelings on him. I hate him.
'So many of my friends wish him dead, I don't.
'He disappointed me because I trusted this person and in that moment I saw him show his true colours.'
Arleta said Sexton had made up 'lies' by claiming that she cheated on her long-term partner.
She said Sexton is 'sick to his head' for coming up with the lies and that he called her a 'f****** b****'.
Winchester Crown Court, Hampshire, previously heard that Arleta found her sister's dead body on her bed when she turned up at the property in Waterlooville because she wasn't returning her calls.
The court has been told Arleta's partner Lucasz Dylewski called 999 from outside Miss Derkacz and Sexton's home on December 28 around 11.30am after Arleta found the body.
Stephen Sexton, 39, muttered an apology to Joanna Derkacz's sister after she found her sibling's lifeless body, jurors were told.
Arleta Derkacz said Sexton appeared 'petrified' and had 'dead eyes' when she arrived at the home he shared with her sister.
Arleta told how she pushed past Sexton to discover Ms Derkacz's 'grey' body on her bed, having allegedly been choked by her partner of three years.
She also claimed that Sexton, holding a knife, told her 'I'm sorry' as she ran out of the house, shouting 'you killed my sister.'
Arleta told police that as she was running out of the house, she thought that Sexton said, 'I'm sorry.'
She told officers: 'I am not sure but I think he said 'I'm sorry'. When I went downstairs and the way he looked at me it was almost like waiting for me to give him a privilege to do it or me to say something so he could do it.
'So I just went downstairs, and he said something when I left, and I remember thinking he said 'I'm sorry.''
Arleta said: '[Miss Derkacz] did say that he was trying to choke her, but she managed to get away and she managed to push him off.
'I know he was aggressive, especially in the last year, and sometimes things he was saying on drugs.'
The trial continues.