You're not truly human until you've been in love.
Humans being what they are, you're unlikely to find your true love the first time around.
There is no love without risk. If you won't risk yourself, then keep your lonely bitterness to yourself. Broken hearts hurt like hell, but do you want to die without any scars?

...therefore, it is better to have loved and lost, than never loved at all. It doesn't mean you won't love and be loved again.