Google has announced "confidential mode" in mobile devices. With the help of it, you can protect sensitive information from unauthorized access. To start confidential mode, just tap the toggle from the menu at the top. Google also has started its own support service for this new feature.
Your thread asks a question, then it seems you know the answer, but actually, you don't. How "confidential" or encrypted are the emails? Do you have to do anything different to receive these if you aren't a gmail user?
After you send an email, it’s pretty much outside your control. Gmail’s new Confidential Mode tries to give you a bit of control back by offering message expiration dates and making it trickier for email to be forwarded on. Confidential Mode, part of the new Gmail interface, works because it doesn’t technically use standard email protocols to deliver the message. Confidential messages are hosted on Google’s servers, instead. This has its downsides—recipients who aren’t viewing the email in Gmail have to click a link to open messages in a browser, for example. Still, it’s a decent attempt at making email secure, and it’s pretty seamless when all parties are using Gmail.