naïveté

from The Century Dictionary.

• noun Native simplicity; a natural unreserved expression of sentiments and thoughts without regard to conventional rules, and without weighing the construction which may be put upon the language or conduct.

from the GNU version of the Collaborative International Dictionary of English.

• noun The state or quality of being naive.
• noun lack of sophistication or worldliness.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Lack of sophistication, experience, judgement or worldliness; artlessness; gullibility; credulity.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun lack of sophistication or worldliness