There is no exact equivalent of mindfulness in Chinese text. I could only describe “being mindful” based on my personal experience as follows:
The term “To be mindful” is still a conscious activity, being reminded that we must be mindful. My experience is…
When our mind are “completely quiet”, we reach a state of total, complete whole body experience. We live our life as if we are in the zone. Everything is spontaneous, natural and effortless. Our body, mind and spirit are working as one. We call this state, “connected, or in sync with our Buddha nature”.
Some call that ”complete surrendering”.