Kindness, I taught my children this and it has served them well.
It takes "courage" to be honest and kind. Being honest and kind require being mindful, in the present, and a knowledge that one one knows or should know what right from wrong. To me, being honest, being kind, that embodies courage..
Honesty. Because if honest to yourself and others you would be Kind and whilst being honest and Kind to will give you the courage to keep doing everything you do or have to do. Knowing that it will all end as it should.
I would teach courage.
It takes courage to be honest.
It takes courage to be kind.
So I would teach courage.