Most of us reacted to the news with cautious/guarded 'optimism'. [=a feeling that something good may happen but will not definitely happen]
He maintains a sense of 'optimism', despite all that has happened.
The early sales reports are cause/reason/grounds for 'optimism'.
(..) You really are the worst brother. I assure you, brother... the sun will shine on us again. Your optimism is misplaced, Asgardian. Well, for one thing, I'm not Asgardian. And for another... we have a Hulk. (..)2018 Avengers: Infinity War