Yes, it could be called sexist saying women are just better at PM then men, it's also a statistical fact and truth.

Truthfully being in California I would like to speak with some local investors to see how they are profiting with their investments here in California.

Anyone that says there is, isn't being truthful to you and is more than likely trying to take money from you.

Any truth to this?

The truth is, no one really knows.  

I'd start by reaching out to local real estate investment associations (REIAs), as well as checking here on BiggerPockets, to identify STL landlords willing to give you the unfiltered truth about the property managers they are using or have used in the past.Be sure to thank these investors generously once you've spoken to them: You'll likely be relying on them repeatedly for additional assistance and advice!

Do I charge extra rent in case she not telling the truth?

But, you need to separate truth from reality.

@Matt Schafer I am going to ruffle a lot of feathers here because I am going to tell the truth and call out the BS in the realm of wholesaling. 

It really depends, and I know that's a suboptimal answer, but it's the truth.