Most people send and receive many text messages a day. we send messages raging from “honey i will be 5 minutes late” to “check out the new bra i got”. We sometimes even send personal information such as bank info without a thought. If you wish to keep your conversation private you should be using Threema. Threema is available on iOS, Android and Windows phone. Security on Threema is just as bullet proof as you can get.
If you wish to read all about how Threema does their security you can do so at https://threema.ch/press-files/cryptography_whitepaper.pdf