Fraudulent; fake; having a misleading appearance.
To fake.
A person who professes beliefs or opinions that they do not hold.
Anything fraudulent or fake.
A person who assumes an identity or quality other than their own.
Certain to act or be a specified way.
Physically secure and certain, non-failing, reliable.
Certain in one's knowledge or belief.
Yes, expressing noncommittal agreement or consent.
Yes; of course.
You're welcome; polite response to being thanked.
Without doubt, certainly.