Google uses different methods to make an educated guess about how users experience your site. They look at elements like site speed – there’s almost nothing more annoying than a page that takes ages to load -, mobile-friendliness, the way you’ve structured your content and the internal and external linking of your pages. Lots of high-quality links to your web page probably indicate people had a pleasant experience with it, right?
In addition to that, Google uses user signals to find out how visitors experience your website. User signals are behavioural patterns that Google sees on your site. If a lot of people leave your website very quickly, they might not have found what they’re looking for. Of course, there are some exceptions to this.