This might be realistic in the case of a girlfriend, but is hard to believe in the case of friends. You can't just decide that loneliness doesn't hurt you anymore, can you?
Or if you can, it would be very interesting to know more. There is a lot of research that points the other way.
There are some good books on the subject. Solitude: A Return to the Self by Anthony Storr was one of the first I read and had a strong focus on psychology. For a more opinionated text, Party of One: The Loners' Manifesto by Anneli Rufus was good at building confidence in living this way.
Judging by what I see on amazon.com, Storr analyzes the life of some famous people that apparently managed to be happy through work despite 'inferior relationships'.
The one I've read is 'Loneliness: Human Nature and the Need for Social Connection' by John T. Cacioppo and William Patrick. It quotes a lot of studies that statistically link feeling disconnected with all sorts of things you want to avoid, including health problems.
Of course, instead of having friends, you can try to avoid loneliness by getting rid of your social needs, in a kind of ascetism. I never managed to do that. On the other hand I read that Alexander Selkirk, the stranded sailor who inspired Robinson Crusoe, suffered terribly from loneliness the first one and a half years, but then got over it completely. Later, back in Scotland, he even regretted his time on the island. I was wondering if this story was true, and if there were other examples.
Secondly, friends are also like women: you'll find a good one when you've really reached a point of frustration where you find yourself swearing that "This is enough of suffering for me! I do NOT need a friend/girlfriend to be happy and to feel fulfilled. If I have to, I'll go by myself just fine, thank you!" OTOH, nobody wants to befriend someone who really wants a friend, maybe just any friend. You can't seek for friendship, it will seek for you.
Third, you should make up your mind about what you want. What do you want from your friends should you become blessed with one? What do you want to talk about with them? What do you want to do with them? Unless you know what you want, you'll just keep bumping into friends or "friends" who want to do their stuff. Nobody is going to come and probe you for subjects that you might want to talk about, everyone just settles for some topic they know you know too. Also, being occasionally brave enough to talk about what YOU want to talk about is a great device to weed out people who can't or won't align with your interests. For example, if you want to talk about life, start doing that and you'll soon find out who will bounce back and who simply can't handle it.
Generally, whatever it is that isn't working will just keep happening again and again until you find a way to change yourself, causing different and possibly more desirable things to keep happening.