spes

Spes, spei is feminine, fifth declension, and one of the very few nouns of that declension you will meet often; res, dies and fides are most of the rest. The genitive and dative singular spei are written out in full in prose, and the nominative and accusative plural are spes and spes, so the singular and plural nominative look identical.

Spes is neutral, not cheerful. It means expectation, and Latin happily says "spes mala", the fear that something bad is coming. The verb is spero, and it takes an accusative and infinitive rather than a "that" clause: "spero te venturum esse". In the church corpus spes sits in the triad with fides and caritas, and there it does mean hope in the warm sense. English despair, desperate and prosper all trace back to it.