I have a Xiaomi Redmi Note 2 running MIUI 220.127.116.11 (latest OTA update, based on Android 5). I encrypted it. Then I restored to factory settings, first from the Android menu then from the recovery menu (volume up + power). The phone still reports itself as encrypted in the privacy settings. In the same menu there is no option to either decrypt or encrypt the device. I can set a lock screen PIN and the phone will prompt for it during the boot sequence. I can also disable any lock screen protection and no questions are asked at boot time.
How can I tell for sure if my phone is encrypted or not? If it is not encrypted, how can I encrypt it please? If only answering the first question please try to give an answer that I can verify experimentally rather than one which relies on me trusting your expertise. I am not afraid of getting my hands dirty.