be somebody's only hope

Our only hope is to run before they've seen us.

They weren't looking at him as if he was their only hope.

Many see him as their only hope for a better life.

Now the only hope would be to work with her.

And you may be the only hope we have, she thought.

By then the only hope was for death, and soon.

In the long run he's the only hope we have.

Our only hope was if he had called in his son.

What if our going back in time is Earth's only hope?

The only hope is if the money comes with a price.