I’ll go first: “You have to have children when you’re young,” told to me when I was in my late 20s, with no desire to ever have kids, and no means to support them, by someone divorced multiple times with at least one adult child who does not speak to them.
Also: Responding to “How do I deal with this problem?” questions with “Oh, don’t worry about it, it’s enough that you’re even thinking about it!”
I think it can be helpful as a first sentence, but it needs more. “By loving yourself, I mean treat yourself better. Get a style and work it. Work out occasionally. Eat better. Find a hobby. Find another. If you want somebody else to love you, you have to first take care of yourself or nobody will think you could take care of them. Secondly, you have to make yourself into a person that’s interesting because anybody can be nice. You need more than nice. Third, having a life is how you meet people, and you gotta meet 'em before you can ask 'em out. That’s why you have to love yourself first.”