The exact words that you choose affect tone, attitude, imagery, and, voice. Just as with your speaking tone, your written tone can reveal any emotion or attitude a person can feel. Tone can be positive or negative, happy or sad, angry or peaceful, hopeful or desperate, and so on.
Since this word means lacking of sympathy or concern, you'd need to find the opposite of being a " down to Earth person". That means that the person is openly honest and values other's opinion. Hence the answer being Indifference.
