How does a gentile annul a vow? Also, do gentiles have equal laws of oaths to Jews? Thank you
Josh K commented that 'We have this question as "how does a Ben Noach annul an oath" and the answer reached (if memory serves) is "keeping an oath is not one of the 7 Noahide laws". I am unable to find that question now, however." That answers - at least partially, the second half of our question - do gentiles have equal laws of oaths to Jews?
Encyclopedia Talmudis [volume 3 page 357 beginning of page, and page 310 last paragraph of 1st column] brings that some authorities want to say that gentiles are obligated to keep their vows.
[However, the first part is - How does a gentile annul a vow? That is not answered. It also therefore doesn't answer the question that it was replying to which is the same as our first part. The reason it's not answered is that even if they are not absolutely obligated in keeping an oath, it's obviously very immoral not to. The Rambam actually implies [Melachim, 10, 10. (That's in Shoftim which is in his Mishneh Torah)] that it is praiseworthy for a gentile to keep as many of the mitzvos as he can. (Besides for a few which he may not - Shabbos, maybe learning most parts of Torah.)]