You can read a written transcript of Thunberg's talk by clicking this link. As an alternative, you can click this link, to see a video of the actual presentation.
Here is what I would call the "pull quote," a short summary of the essential point made in Thunberg's talk:
Yes, we do need hope, of course we do. But the one thing we need more than hope is action. Once we start to act, hope is everywhere. So, instead of looking for hope, look for action. Then, and only then, hope will come.
Out of action comes hope. That's how it works. Not the other way around!