una rondine non fa primavera significa in inglese

one swallow does not a summer make▼(one instance of an event does not necessarily indicate a trend)
phrase
[UK: wʌn ˈswɒ.ləʊ dʌz nɒt ə ˈsʌ.mə(r) ˈmeɪk] [US: wʌn ˈswɑːlo.ʊ ˈdəz ˈnɑːt ə ˈsʌ.mər ˈmeɪk]