I guess Tuta is the way to go.

nostr:nevent1qqs22qy3q0j78dpjulpgduf8c353kskx2nnfhnqcade9s37j7ltkqzgpz4mhxue69uhhyetvv9ujuerpd46hxtnfduhsygqpmhhz3xc696ggwn9rg2985s28vjnv45dtl25ctsspu74d59kn3spsgqqqqqqsjae2ph 

 If expecting a communication to be private, best not to use email at all. 

Some kind of self-hosted or peer-to-peer encrypted chat would be a better way to go than email.  

 Unless self-hosting makes security holes. There will always be attack vectors, but I'm looking at who stands for freedom versus those that bend over to help tyranny.