Naïve, a.
Etymology: [F. naïf, fem. naïve, fr. L. nativus innate, natural, native. See Native, and cf. Naïf.]
Having native or unaffected simplicity; ingenuous; artless; frank; as, naïve manners; a naïve person; naïve and unsophisticated remarks.
Shades of meaning
Fernald has no entry of its own for naive; he lists it under candid.
Where he writes about it:
On the other hand, artless, guileless, naive, simple, and unsophisticated express the goodness which comes from want of the knowledge or thought of evil. — from candid