How do you know that the news and videos she was publishing were real?

Because news organisations like the FT or the BBC published the same news that she had published two or three days before.

Granted, she was not the only one publishing them on Twitter, but she was the one I was following the most. Also to add, news organisations like the FT or the BBC were only publishing news that could be taken for a political spin, like in the case of Li Wenliang, they were not publishing news about people committing suicide on their home as not to infect their loved ones or desperate phone calls made by people who were trying to get their loved ones into an hospital (which were already full by that point).

Also, many of the hospital scenes I was seeing on Twitter on her account are similar to what now surfaces from hospitals located in Northern Italy.

But you see the obvious concern, right? If news organizations publish some but not all of the same news she's reporting, that could mean that they're selectively skipping news to push a political angle - or it could mean that she's selectively adding fake news for her own political motivations. My inclinations are not to break the tie in favor of the person posting about a mystical connection between coronavirus and the shape of the Wuhan train station.