ingénues

Ingénues are young women characterized by innocence, naivety, and guilelessness—or the theatrical roles portraying such characters.

The term comes from French, where it means ingenuous or artless.

In film and theater, an ingénue is a stock character: the sweet, wholesome young woman, often a romantic interest.

The word can carry slight condescension when applied to real people, suggesting someone charmingly unsophisticated or perhaps not as innocent as she appears: She played the ingénue well past forty.