In my experience this is very bad advice:
Can you see why this is insane? If not, ask yourself this question: why would your loving someone enable them to transform themselves? You're not God so your love isn't that special or powerful. Nothing against you personally, no one's love is that.
And why would you want to be able to transform them? Isn't that manipulative?
But maybe this text wasn't written for people looking for someone to love. Maybe it was written for people looking for someone to love them. People who sit around and imagine that someone loving them will enable them to transform themselves. People who feel they've been cheated of love they deserved and have spent the rest of their lives waiting for other people to make the first move. They're not going to take a chance. They've been hurt before and they want someone else to stick their neck out first.
They've never thought any of this out. They just feel cheated and hurt and so they hold back. They don't need to be empowered to transform themselves. All they need to is to do it. It's not easy, of course. It would be bloody hard work. But they're the only ones who could do it. Believing that someone else needs to love them just as they are is just an excuse to avoid facing this.
Whatever you do, don't get into a relationship with someone like that.