Sentence:  “I must not hope to be ever situated as you are, in the midst of every dearest connexion, and therefore I cannot expect that simply growing older should make me <WSD>indifferent</WSD> about letters.” / “<WSD>Indifferent</WSD>! Oh! no—I never conceived you could become <WSD>indifferent</WSD>. Letters are no matter of indifference; they are generally a very positive curse.” 
Meaning of the word marked with <WSD> tags:  Not caring or concerned; uninterested, apathetic.