Google always sends an email if i sign in from a different IP?, Any ideas?
Here is what is happening: google has been tracking your logins ever since you first made your email. By now they have an exact fingerprint on you that allows them to determine whether or not it is really you logging in or not. Then one day they see you logging in from a foreign country using a browser they have never seen before. "Uh oh! Must be a hacker!" and they lock you out of your account, or at least send you an email.
What really happened of course is that you just logged in from Tor Browser. Once you log back in to your account from your usual non-tor browser and tell them that it was really you, they will mark you in their system as a tor user. From then on, logging in from foreign countries and jumping across continents in milliseconds is no longer strange, and they will no longer lock you out of your account when you log in via tor.
As far as safety goes, yes, you are safe in the sense that your communications are end-to-end encrypted to the real google through the tor network. (Note that many may consider using google at all to be unsafe due to their spying habits; this has nothing to do with whether you use tor or not though.)