Is Emal Secure?

Mortgage and real estate industry ask me to send them sensitive information through emal. If i'm sending it from some domain that you don't control, emal is not secure. You don't know many hops it's taking before it gets to your network. It drives me absolutely insane when companies, industries that deal with sensitive data Don't know what they're telling people to do. I would just put the same answer for all these three security questions.