Basically, the letter was from a man I was dating that I have known for a long time. In it, he uses 1000 words to express this: I love you, I care for you, but we have too many differences and are not compatible. I told him I agree and to have a nice life. He wrote back that I mean the world to him and he never loved anyone as much but will let me go if that's what I want.
I really had feelings for him. I posted the letter because I don't have much experience with men, and my parents, although married for 40+ years, were not the best role models. So, I posted here for guidance from people who know better than I do and could tell me if they thought he was being sincere or just being manipulative. I deleted it because I felt stupid for believing him in the first place.
I hope this helps someone.