You must ask yourself these series of questions and do these spot checks:
-Is it labeled as an ad?
-Is it a reputable publisher? (google is NOT a reliable source as it is not a source at all but will help you find information about the website address)
-Check the security status in the address bar
-Typing the website's name in a search engine gives you information on how highly used it is.
These are some of the ways the address can help you check reliability of the website.