I made a service to share passwords easy and secure but never promoted it. It's called instapass.io I noticed that people besides my friends and clients actually started to use, so maybe it will be helpful for you too! You share one-time self-destruct message using one time links and I won't even be able to see what you wrote.
How does it work? When you generate a message the client-side makes a random password and use that to encrypt the message. The password is appended as an anchor tag which all modern browsers never send to the server. This way, I don't even know what you shared. Why this and not one of the fancy solutions that exist? Time and complexity. In my experience, people never get around to setup the services especially if you're a consultant like me. And then comes the part of trying to explain to a non-technical person how a master password is and how to share it and signup etc. Instapass offers high security, zero setup time and works for non-developers.
Martin.