Breakdown of Она мечтает о красивой свадьбе.
она
she / it (for a feminine noun)
красивый
beautiful
о
about (о, об, обо)
мечтать
to dream
Questions & Answers about Она мечтает о красивой свадьбе.
Why is "of" translated as о in this sentence? Doesn't о mean "about"?
In English, we say "dream of" or "dream about" interchangeably. In Russian, the verb мечтать (to dream / to wish) must always be followed by the preposition о (or об before a vowel) and the Prepositional case.
Why do красивой and свадьбе have these specific endings?
Because they follow the preposition о, they must be in the Prepositional case. The feminine noun свадьба (wedding) changes its -а ending to -е to become свадьбе. To match the noun, the feminine adjective красивая (beautiful) changes its ending to -ой, becoming красивой.
Can I use мечтать to talk about a dream I had while I was sleeping?
No, мечтать is only used for daydreaming, wishing, or having aspirations for the future. If you want to say you dreamt about something while asleep, you would use the phrase видеть во сне (to see in a dream) or the verb сниться.