Bonafide emails from Google will always be from the google.com or gmail.com domains. Fake emails may include.....
Erm, I get the impression from your paragraph that you don't fully understand the implications of what you're saying.
For the absolute avoidance of doubt and clarification, simply looking at email addresses or domain names
IS NOT the way to tell if an email is kosher.
"From" addresses can be forged .... incredibly easily, and with no special software, coding or "hacking" required.
So as far as "from" addresses go, to paraphrase Mr Starr's song ....
"FROM! What is it good for? Absolutely nothin'!"
In order to correctly evaluate the authenticity of an email, the
ONLY way to look at the email source and go through the full raw email headers.
And finally, as has already been mentioned, even if the email looks Kosher based on raw headers, but contains an unexpected attachment, or a link to a security-sensitive function ... you should be weary and get in touch with the sender before proceeding further.