Why would you need to believe a claim when you can verify the results yourself? All you need is a Google sheet or Excel that can do quote lookups and record Saul’s buys and sells in his end-of-month posts at the link I gave above.
I can help you get started. As an example, Saul says that he first bought Twilio (TWLO) in his Jan 2018 update at My portfolio at the end of Jan 2018
In your Google Doc, put the date 1/31/2018 in cell A3 in Column A. In Column B, in the same row, put the stock symbol TWLO. To pull the quote for TWLO for 1/31/2018, enter the following formula in Cell C3.
=index(GOOGLEFINANCE(B3,"price",A3),2,2)
Then cell C3 will populate with TWLO’s closing price on 1/31/2018 which was $26.24.
If you go through his monthly posts, you will find he held TWLO for 21 months (almost 2 years!) and said he sold it during November 2019 at this post My portfolio at the end of Nov 2019
So pull the quote for TWLO for 10/31/2019 using a new row in your spreadsheet, and you will see it closed at $96.56. You can therefore calculate that his return on TWLO was around 264% over this 21-month period. The exact buy and sell dates may be off by a couple weeks on either side, but when you’re holding stocks for multiple years, it’s a good ballpark figure.
To validate the results for his entire portfolio from 2014 through 2022, enter more rows and columns in your spreadsheet for each stock he says he owns in the percentage he says he owns, and record his buys and sells each month.
So his results are easily verifiable, but you need some spreadsheet skills and some hours to put in the work. If you do that, you can convince yourself, and you don’t need to take my word for it or to depend on hearsay and “beliefs”.