Ben Noah and his obligations regarding vows

Question

A hypothetical case (based on a somewhat similar real one): Ben Noah in the process of giyur. Stood before the Beis Din and was asked question 'Will you follow the mitzvot as fully as a goy can up until the end of the process of giyur and completely after the process is done?'. Ben Noah said 'I will'. Will he sin if he won't, as fully as he can (e.g. no 100% observance of Shabbos, etc), observe the mitzvot even before he becomes a ger?

Of course the 'level'/kind of potential sin is not like for a Jew, but could it be considered false statement or maybe oat/vow, assuming the Ben Noah already is fully sure (has the mindset) he will confirm his observance of halakha at the next Beis Din meeting (even though he may not keep his word and follow the guidance of the Beis Din)? Will he be liable to punishment either from Shamayim or from a Beis Din? Remarks:

• Again, this is a hypothetical case.
• Please note rabbinic prohibition against taking oats is not binding for the goyim.
• Please give a reason if you downvote, so I can ask better questions in the future.

Answer 1

See #2 here from Rabbi Mordecai Kornfeld for a lengthy discussion around the obligations of a Ben Noach to keep his word. The perspective he concludes with is:

This approach is also suggested by the MISHNEH L'MELECH (Hilchos Melachim 10:7). The Mishneh l'Melech adds the examples of Avraham and Yitzchak, who made Avimelech make an oath. It is evident from there that Nochrim are commanded to keep their promises.

However, what is the specific commandment, according to this approach, that obligates Nochrim to fulfill their oaths? After all, it is not one of the seven Mitzvos of Bnei Noach. The MESHECH CHOCHMAH (Shemos 20:7) explains that although there is no explicit Mitzvah that requires Nochrim to fulfill their oaths, this obligation is an obvious moral responsibility that falls in the category of a "Mitzvah Sichlis," a logical Mitzvah. Since it is a "Mitzvah Sichlis," a Nochri receives a punishment from Shamayim for violating his oath, even though Beis Din cannot punish him (as it is not one of the seven Mitzvos of Bnei Noach). This reasoning is also alluded to by the Mishneh l'Melech (ibid.).

Answer 2

Here is a list of the seven Noahide commandments:

1) Do not murder.
2) Do not steal.
3) Do not worship false gods.
4) Do not be sexually immoral.
5) Do not eat a limb removed from a live animal.
6) Do not curse God.
7) Set up courts and bring offenders to justice.

It's debatable if law #7 also prohibits false testimony, but it sounds like our case is one where the prospective convert intended to answer truthfully at the time.

So, if this person meant to follow through, and then somehow slipped, that's not false testimony.

Since modern Jewish courts typically don't force people to swear in God's name, any affirmative answer in beis din isn't an official "neder" or "shavua". That is to say, even if a Jew answers "yes" to a beis din regarding future conduct, failing to act in accordance with the request of beis din doesn't make the Jew violate the sin of breaking a vow.

If a Jew would not violate that law in this case, all the more so a non-Jew. [This is all assuming that law #6 prohibits non-Jews from using God's name in an oath, and then not fulfilling that oath]

Answer 3

Since it is a מצווה שכלית ("rational" mitzvah), as others have said, I find it hard to imagine it not being binding on a Ben Noach.

Furthermore, I would suggest a more formal obligation here: that the obligation to keep an oath precedes the very idea of mitzvos since our obligation in mitzvos is viewed as the outgrowth of an oath. Thus we have the phrase "מושבע ועומד מהר סיני" for example.

It would seem to fall under the category of דרך ארץ קדמה לתורה.