How to know if a website is safe to use or not? 

It is not secured by SSL security if chrome says. To check if it is secure or not, see the lock icon when you browse any website on chrome. Wait until the website loads. Have a good connection and then... If ⓘ is shown instead of 🔐, it is not secure by SSL

Check the website reviews on Trustpilot

Check website reviews on Capterra

Search if the site is legit or not on Google.