What's the safest email to use?

Could you elaborate on the factors that determine the safety of an email for use in the realm of cryptocurrency and finance? Given the sensitivity of the information involved, it's crucial to ensure the utmost security. Is there a specific email provider that's widely considered to be more secure? Or are there certain encryption and security measures that should be implemented regardless of the email service? I'm interested in knowing the best practices to ensure the safety of my email correspondence in this industry.