You can't.
If they're not showing interest, it wouldn't be sincere of them anyway even if you could convince them to want to be your "friend" out of pity, and then you are stuck with an insincere relationship that is doomed to failure.
There are very, very few people out there, if any at all, you will find that will be true to you-- and positively zero that will like you based out of pure altruism. If they think it's too much work they'll just spend time with people who are easier for them to deal with, and unfortunately due to our intensity, which can come across as intimidating, and tendency to cause embarrassment to ourselves and/or people we are hanging out with, it's easier for them to work with someone who is on their wavelength.
This isn't to say you can never find lasting friends-- only that if you try too hard, you will fail. I'm 29 and I have no real friends, so...
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