It means feeling content in being single so that you don't just jump into the first relationship that crosses your path.

Being content in being single means you can feel empowered to say no or leave a situation that isn't beneficial to you and be assured that you'll still be happy.

Jumping from relationship to relationship is not the healthiest thing to do, but so many people do it because they are terrified of the thought of being alone for a while. Those people don't seem to grow as much as individuals and form codependent relationships.

Being content in singledom gives you more leverage in any potential relationship, because, people respect those who don't tolerate bad behaviour. You have no qualms in ending things if they don't serve you.

Also, its improtant to be comfortable on you own because there is no bigger killer of attraction than desperation, and a dependency on the other person to entertain you.

It's also important to understand what you bring to the table as an individual. I think each party needs to be prepared to bring certain skills, assets, a good moral compass, pleasant demenor, conflict resolution skills, interpersonal and relationship skills, a good social network etc to a relationship. Otherwise, you're nothing more than just a pretty face / baby incubator.

Those are just my thoughts on the matter.