DICTIONNAIRE ALLEMAND-ANGLAIS

The German word sensibel is a false friend which has to do with feelings rather than the mind, and so it corresponds to the adjective sensitive, not sensible. Sie ist immer ein sensibles Kind gewesen therefore translates as She has always been a sensitive child.

The English word sensible is most commonly translated by vernünftig. So if you want to tell someone in German: Be sensible! you could say Sei doch vernünftig!