Worried about stds

So I have tried to actually go out with multiple people to just get a one night stand in but I'm always worried that you never know if they have an STD or every time before we meet and have the deed done. I'm always asking if they've ever had an STD or if they have papers proving that they don't have an STD. I really do have to ask, is that normal to worry about that sort of thing? Do I just take them for their word? Or do I actually need to get vital proof that they don't have an STD?