Step 1: Understand the word.
Hopeful means expecting something good to happen. It has a positive meaning.
Step 2: Compare the options.
Optimistic also means positive and confident about the future. Doubtful, hopeless, and pessimistic all show a negative or uncertain feeling.
Step 3: Select the synonym.
The closest meaning of hopeful is optimistic.
\[ oxed{ ext{Option 1: Optimistic}} \]