How do you know if a website is fake

I bought 3 bags off of michaelkorscoshop.com 4 days ago and still haven't gotten a notification about when it's going to be delivered. Each bag was $39-$65 (it was a sale). Now I'm starting to think its fake.... I used a debit card btw.

That's fake. The official site Michaelkors.com is the ONLY site in the world selling authentic Michael Kors that is legally allowed to use the Kors or Michael Kors name in their domain name. Every other site is fake and breaking the law - it's called Trademark Infringement 

The site is also breaking the law by failing to provide a registered business address and contact phone number. That is the most basic requirement for ANY e-commerce site. The only reason they don't put an address or phone number is so you can't find them to sue them when you discover you got scammed. They only have a free @outlook.com address - NO real business has one 

Cancel the order on the site, then call your bank ASAP to report you got scammed, cancel that card and get a new one

It sounds fake. Michael Kors site is michaelkors.com. I would try to cancel the order and if you can't, block it on the card you used. 

The best way to tell if it's the legit site is good the name. The first one coming up will be the legit site. This one isn't that - so even if they deliver, not likely to be legit products. 

Shop known sources. There's a reason stuff was cheap.