To make sure that you are connected to the right secure website you can use Fingerprints website.
You compare the fingerprint of its certificate in your browser against a trusted source that provides you with fingerprint records.
Looking up fingerprint certificates because each web browser handles this in a different way.
Now compare the fingerprint displayed in the web browser to the certificate pulled by the script on the GRC website.
Also some companies can use multiple certificates that’s mean that the certificate differs even if you are connected to the real website or server.