I am serious. Maybe there is something lost in translation. My dictionary gives me:

   disposition <n>, nature <n>, nature <n> of a person,  nature <n> of a thing, temper <n>, mettle sb. is made of <n> [archaic], natural <adj>, quiddity <n>, particular nature <n> (of a matter), essence <n>, suchness <n>

The examples make me think, that English indeed does have this meaning of the word "nature", and it's only you who doesn't know this, but maybe you would prefer a different word?