Learn Romanian: Fata fericită zâmbește des. - The happy girl smiles often.

Zâmbește comes from the verb a zâmbi (to smile). Verbs in this group use -esc for 'I' (eu zâmbesc), but they change the suffix to -ește for 'he, she, or it'. Since we are talking about the girl (ea / she), we use zâmbește.

Where is the word for 'the' in this sentence?

In Romanian, the word for 'the' is attached to the end of the noun. The base word for girl is fată. To say 'the girl', you replace the final -ă with an -a, making it fata.

Why is the word order Fata fericită instead of Fericită fata?

Unlike English, Romanian usually puts the adjective after the noun it describes. So 'the happy girl' translates literally to 'the girl happy' (Fata fericită). The adjective fericită also ends in -ă to match the feminine noun.

Does the word des change if more than one person is smiling?

No, des acts as an adverb here, meaning 'often'. Adverbs describe the verb and never change their form, no matter who or how many people are doing the action.