The honest answer is: No, Mexico City is not safe from earthquakes in the sense of being protected from them. Mexico City is in one of the highest seismic risk zones in the world.
However, "safety" is relative. It depends on whether you mean the probability that an earthquake will occur (very high), potential damage (very high), or the ability to survive with proper preparation (possible).
Earthquakes will occur in Mexico City. There will be another major one in the next century, probably within the next 50 years, based on historical patterns. The city has experienced at least 3 catastrophic earthquakes in the last 150 years (1985, 2017, and others).
What you CAN do is prepare properly. Live in a structurally sound building (post-1985 construction). Maintain an emergency kit. Know where safe spots are in your home and workplace. Know how to contact your family. Get appropriate insurance.
If you plan to live in Mexico City, accept that seismic risk is part of reality. Most residents live normal lives, but with smart preparation.