pin (one's) hopes on (someone or something)
To have expectations that are tied to the success, performance, etc., of a particular person or thing. Why are we pinning our hopes on him when we know he's not popular enough to defeat the incumbent? I had pinned my hopes on this promotion, so I was crushed when I didn't get it.
ˌpin your ˈfaith/ˈhopes on somebody/something
put your trust in somebody/something; hope for somebody/something: He’s pinning his faith on the revival of the economy.The idea that he’ll be out of prison in five years is all she’s got to pin her hopes on.