kindliness vs kindness

[keannu]

What is the difference between "kindliness" and "kindness"?

mo2-29
ex)...one little boy wrote Wilhelm II a simple, sincere letter, glowing with kindliness and affection...

 

[Tdol]

A the little boy probably hadn't had the opportunity to be kind to Wilhelm II, then kindliness would refer the the quality of his character rather than any actual deed.