"I absolutely thought I was going to die," the billionaire celebrity told a Paris court on Tuesday, recounting her shock and fear during the attack, in which she thought she was going to be raped and shot.
"I thought about my sister, thought she would walk in and see me shot dead and have that memory in her forever," she said.
Kardashian cried as she recalled the start of the attack, in which the suspects are accused of tying her up with zip ties and duct tape before making off with jewellery, including a $US4 million ($A6.2 million) engagement ring given to her by her then-husband rapper Kanye West (now known as Ye).
Dressed in a smart black outfit by British designer John Galliano and wearing shiny jewellery, Kardashian, 44, recalled the details of the attack.
"We were leaving the next morning so I was just packing up, it was around three in the morning. I heard stomping up the stairs when I was in bed," she said, adding that men dressed as police officers barged in.
"Then I heard one of the gentlemen forcefully say 'ring! ring!' in English, with an accent, pointing," she said. One of them pointed a gun at her.
"I was pretty hysterical and I just looked at the concierge and told him 'What is going to happen to us? I have to make it home to my babies'," Kardashian said.
She said at one point she feared she was going to be raped as the robbers threw her on the bed and one of them grabbed her leg. "But he ended up tying me up and closed my legs," she said.
Kardashian said the intruders did not hit her.
"I was grabbed, and dragged into the other room, and thrown onto the floor, but wasn't hit, no," she said.
There was another emotional moment in court when a letter of apology written by 69-year-old defendant Aomar Ait Khedache, nicknamed "Omar the Old," who can no longer speak, was read out.
"I'm honestly emotional about it," Kardashian told the court, in tears.
"I do appreciate the letter for sure, I forgive you," she said, looking at Khedache.
"But it doesn't change the feelings and the trauma and the fact that my life was forever changed, but I do appreciate the letter, thank you."
Khedache is accused of being the ringleader of the robbery, which he denies. His response to Kardashian's words was read out by the court.
"Your forgiveness is a sunshine that has enlightened me ... I am forever grateful," he said.
The attack, during Paris fashion week, changed a lot of things, Kardashian said, including prompting her to increase her security.
"It changed the way that I feel safe at home. Now I have between four and six security at home for me to feel safe," she said. "I can't sleep at night if there aren't multiple security people."
Ahead of Kardashian's testimony, her stylist Simone Harouche, who was asleep in the same luxury hotel flat at the time of the attack, told the tribunal of the "terror" they both felt during the robbery.
"She was beside herself, I've never seen her like that before," Harouche said.
"She just was screaming and kept saying we need to get out of here, we need help, what are we going to do if they come back."
Harouche also cried at times during her testimony, and said she had changed careers and underwent therapy because of the robbery, which she said caused her post-traumatic stress and made her fearful of being around celebrities.
In all, nine men and one woman are being tried by the criminal court. Five of them - all men - face armed robbery and kidnapping charges and potentially risk being sentenced to life imprisonment.
Most of the jewels, including the engagement ring, have never been recovered.
