Ostensible (ah-sten-sib-ul)

(noun) Appearing to be true, but not necessarily so. Pretended.

Examples:

1. The ostensible reason June offered to cook dinner was to stay in and relax, but really she was anxious to show off her culinary skills.
2. While many accepted desire for American prosperity as his ostensible motivation for seeking presidency, June exposed tax records that showed he was much more interested in personal financial gain.