The Library can't guarantee that an internet site is going to be okay (whatever that means - accurate, current, scholarly, etc.) What we can do is give you some tips for evaluating websites, and tell you to ALWAYS check with your professor before you start using or citing websites.
Consider the date/is it new/updated? (Is the page dated? Is the information updated? How can you tell?)
Where is it from? (Who has posted the page? Is it part of something else? Can you link to information about the site?)
Who wrote it? (Are the authors identified? Are their credentials listed? Can you find the authors independently as researchers in this field?)
Are there any references? (A bibliography or list of references? What type of items are in the list - books from university presses, scholarly journal articles, reputable websites? )
How does the page look ?
These are some of the things you need to consider when you are looking at websites.