Sentence:  The letter, perhaps, began in bitterness, but it did not end so. The adieu is charity itself. But think no more of the letter. The feelings of the person who wrote, and the person who received it, are now so widely different from what they were then, that every unpleasant circumstance attending it ought to be forgotten. You must learn some of my philosophy. Think only of the past as its <WSD>remembrance</WSD> gives you pleasure. 
Meaning of the word marked with <WSD> tags:  The state of being remembered, or held in mind; memory, recollection.