Ventura, a rhythm and blues singer known as Cassie who took the stand wearing a turtleneck dress and a dark jacket, is the prosecution's star witness in the high-profile sex-trafficking criminal case against Combs.
"He said that it would ruin everything that I had worked for, that it would make me look like a s***. That I would be shamed," Ventura said, calling the threats "horrible and disgusting"
"Nobody should do that to anyone," she said.
Jurors saw a 2013 text where Combs told Ventura he deleted the videos, but Ventura said she still saw them on his devices on several occasions.
Ventura told the jury on Tuesday that she took part for a decade in Combs' drug-fueled parties known as "Freak Offs," often fearful he could become violent if she didn't, leaving her with black eyes and bruises all over her body.
On Wednesday, the third day of testimony in Manhattan federal court, Ventura, 38, told jurors that while fighting back sometimes slowed Combs down, it usually just made the abuse worse.
"It would just make him more violent, make him stronger, make him want to push me harder," she told jurors.
Combs, 55, is being jailed in Brooklyn when not in court. He wore a light sweater over a white collared shirt to court on Wednesday.
Combs has pleaded not guilty to five felony counts of racketeering conspiracy, sex trafficking and transportation to engage in prostitution. If convicted on all counts, he would face a minimum 15 years in prison and could face life behind bars.
Earlier this week jurors saw a 2016 surveillance video from the hallway of a Los Angeles hotel where a towel-clad Combs threw Ventura to the ground and began to kick her. She said the video was taken after a "Freak Off" where Combs gave her a black eye.
Combs has apologised for the video, and his lawyers have said prosecutors have tried to improperly punish him for his "swingers" lifestyle. They are expected to cross-examine Ventura after she finishes her direct testimony.
Jurors were shown texts on Wednesday from after the hotel incident in which Combs wrote to Ventura to ask her to come back because the police were arriving.
Ventura replied that she would not return because she had a black eye, a fat lip and a movie premiere the next day that she wanted to be rested for.
"You are sick to think it was ok for you to do what you've done," Ventura texted Combs.
"Please stay far away from me."
Jurors viewed photos of Ventura with Combs at the movie premiere. Ventura told jurors she was hiding bruises with makeup and had to change outfits to conceal some of them.
The criminal trial could take up to two months. Combs also faces dozens of civil lawsuits by women and men who accuse him of sexual abuse. He has denied wrongdoing, and said his relationships were consensual.
Ventura, 38, testified earlier that she once viewed her relationship with Combs, which began in her early 20s, as her first real adult relationship.
But she said Combs became more controlling as the "Freak Offs," which she said lasted as long as four days, took over their relationship and derailed her music career.
Also known during his career as Puff Daddy and P Diddy, Combs founded Bad Boy Records and is credited with helping turn artists like Mary J Blige, Faith Evans, Notorious B.I.G. and Usher into stars in the 1990s and 2000s.
