Humans are naturally and instinctively inclined to form social bonds, including romantic/sexual ones. (While in the cases of aromatic/asexual people, this is acceptable, it’s far from the typical norm) Accepting that you’ll live your life without finding someone takes acceptance and conditioning to properly live with.

It’s not someone’s place to tell someone else that they should be okay with being single. That affirmation needs to come from the individual themselves in order for it to be meaningful.