I am asking about the situation about a convert-in-progress who lies at some point during the conversion process, either--more to-the-point--in response to the prefatory questions about personal circumstances, observance, and lifestyle asked by the Beis Din, or in response to the vows made (to be m'kabel ol, etc.) at the time of conversion. We learn in a few places that b'dieved, it doesn't affect the convert's status unless one can all but prove that the convert was insincere in being mkabel ol. But what if the convert merely lied in response to other questions by the beis din? I don't ask if he is still Jewish. It seems he is. I ask, was this l'chatchila a sin?
If so, on what account? -- Since I believe the person answers the questions before the tevila in most cases, it is unlikely that the person is Jewish at the time he answers. My knowledge of the mitzvos shel b'nei Noach is hardly vast, but I've never heard "be honest with batei din" among them - -although arguably it would make sense.
Do any laws govern this, then? If not, what reason would a prospective convert have to demand honesty of himself in this situation? (If there are no applicable halachos, I don't see that Yiras Shamayim strictly speaking comes in to play.)