I want to show hit number for a page. I found Viewslifetime. I am sorting this Descending. So what does ViewsLifeTime means?
ViewsLifeTime is a search managed property which stores the life time view count of a page, list item, web etc.
So, you are correct in using this property to show the view count of a page.
By sorting it in desc order, you will show the most viewed page in a site, web etc based on your search configuration for the webpart