Persiste di is an Italian phrase that means "to persist in". It can be used to express that someone is continuing to do something despite the obstacles or challenges they may be facing. For example, if someone is determined to finish a difficult task, you could say "persiste di finire il lavoro". It can also be used to express encouragement or to urge someone to keep trying, for example, "persiste di imparare la lingua" which means "keep trying to learn the language".