I was reading a sermon by a Tenrikyo minister talking about true sincerity or shinjitsu. He was saying that we must have true sincerity or makoto shinjitsu; saying that this is what God wants from all of us.
But what is sincerity? According to Webster, sincerity is:
The quality or state of being sincere: honesty of mind: freedom from hypocrisy.
How do we get to this state of mind? In the Ofudesaki, God gives us step-by-step instructions on how to reach this state. This is not an easy task, as God compares it to digging up a root. God tells us that there are 5 dusts or evil pathways that we need to remove from our minds. These dusts are regret, covetousness, self-love, greed, and arrogance. When and if we reach this state of mind, God promises that we will live the “Joyous life”.
True sincerity of the mind means a mind without the 5 evil dusts that are mentioned in the Ofudesaki. How do we remove these dusts from our minds? God first wants us to understand our own hearts (mune), as God tells us we do not understand the heart or mune in the first verse. What does our own heart (mune) do? It helps us purify our minds. This information and how to purify our own minds are all in the Ofudesaki. God wants us to have true sincerity or a pure mind!
Heaven's Truths, in Healing the Body 