The claim of this fact is "People who are single are happier" followed by a more detailed description saying, "People who are single are happier because they are living their most authentic lives without having to worry about someone else." This is a very strong claim backed up by only one source, which is BuzzFeed.news is not a very credible source. Still, it used some US Census research, which is credible. However, the US Census research only yielded the fact that it is more common to see single-person households now than before. Yet, had nothing to do with single or coupled relationships and their happiness. Although this claim may be true in some cases, it can also be false in others; this claim is very subjective, so we can't determine whether it's true or false because it varies from person to person. Therefore, I answer that this claim is neither true nor false, just a strong opinion.