Both men interested in Catherine comment on her good nature.
In chapter 15, just before JT leaves Bath, in his awkward conversation with Catherine he says "That is kind of you however--kind and good natured.--I shall not forget it in a hurry.--but you have more good nature and all that, than any body living I believe. A monstrous deal of good nature, and it is not only good nature, but you have so much, so much of everything; and then you have such--upon my soul I do not know any body like you." (How can she resist such praise?)
Then in chapter 16, during the dance, when Catherine has considered Captain Tilney's wish to dance with Isabella a sign of his good nature, Henry says "I only meant that your attributing my brother's wish of dancing with Miss Thorpe to good nature alone, convinced me of your being superior in good- nature yourself to all the rest of the world."
How each plans to deal with her good nature remains to be seen.