It's said that faith is being sure of something you cannot see. This has great implications, but it applies to less important things like buying clothes online. Will it fit?
There are, of course, many sizes to choose from in most online stores, charts of numbers and lengths and pages of reviews. All of that is evidence that the clothing might fit, but not proof. In the end comes the moment where the clothing physically arrives and the customer must find out for themselves if they chose the right size.