disposition, nature
なるほど彼女は美人ではないが、気立てがよい。
I see. She isn't beautiful, but she has a kind heart.
彼女は気立てがいい。
She has a sweet personality.
顔はともかく、気立てはとてもいい子だよ。
Looks aside, she's a really sweet girl.
彼は気立てが良さそうだ。
He seems kind-hearted.
彼女は美人であるばかりか気立てもいい。
Not only is she beautiful, but she also has a lovely personality.