An earnest student is not putting on a performance.
They are focussed upon what is occurring in the immediate moment.
They are feeling what is happening as it is happening; without commentary or reflection.

The student should look neither happy nor sad.
Their expression should be alert, alive and intense.
Shen should be present in their eyes: like a predator stalking its prey.

The form is like that of a falcon about to seize a rabbit, and the shen is like that of a cat about to catch a rat.

(Wu Yu-hsiang)

There is nothing friendly about this description.
It suggests a serious demeanour in which the ego of the student is sublimated by the art.