This is the best way to encrypt your emails. Using GPG Tools and the Public / Private key pair does take a bit to get your head around the way it works but it is not rocket science really. It is a cross platform solution and you can easily get sending encrypted emails that can't be read by governments around the world. Think PRISM and how un protected your emails are now. It is like you sending a postcard - Anyone can read whatever you have written as it travels across the internet.
Now there is the plug in you can get for Apple Mail as well as one for Thunderbird if you prefer which makes it really easy to use. This is the first in a series of videos about how to use GPG Tools so that you can be an expert without having to try too hard.