This is the 568th most frequent Romanian word.
singura
"Singura" in Romanian means "the only one" (feminine) or "alone" (feminine).
In this sentence, 'singura' is used as an adjective in the feminine singular form, meaning 'the only one'.
Sunt singura care a terminat proiectul la timp.
I am the only one who finished the project on time.
Here, 'singura' describes the noun 'cale', emphasizing exclusivity, i.e., 'the sole way'.
Aceasta este singura cale către succes.
This is the only way to success.
In this case, 'singură' expresses an emotional state, functioning as a predicate adjective meaning 'lonely'.