Which preposition to use with inwardness

of Occurrences 31%

But to him the true inwardness of spontaneous play lies in the fact that it is spontaneousso far as anything in the universe can be spontaneous.

to Occurrences 1%

I don't think Sir James himself has much inwardness to him, but certainly his son has shown us only the outermost shell.

Which preposition to use with  inwardness