It wasn't just the evidence of the assault. It was Trump accidentally caught on an open microphone bragging about getting away with sexual assault.
Not sure if I can link to Trump's statement; it's crude and obscene. I'll check with mods. But you can find it, if you look.
It's well-documented.
On October 7, 2016, one month before the United States presidential election that year, The Washington Post published a video and article about then-presidential candidate Donald Trump and television host Billy Bush having a lewd conversation about women in September 2005. Trump and Bush were on a bus on their way to film an episode of Access Hollywood, a show owned by NBCUniversal. In the video, Trump described his attempt to seduce a married woman and indicated he might start kissing a woman that he and Bush were about to meet. He added, "I don't even wait. And when you're a star, they let you do it. You can do anything." (followed by an obscene description of what he liked to do)
Trump claimed he was able to sexually assault women generally, not Carrol specifically. It badly damaged his credibility when he denied the attack.
The court found Trump to be the attacker and Carroll the victim. He has a history of that kind of thing.
The standard rapist defense... "she was asking for it."