I conducted a wedding ceremony for a converted bride, and the wine was not mevushal (this is rare, but it happens). I forgot that her mother is a non-Jew and continued as usual, so after the birkat eirusin, I gave the groom to drink, took back the cup, and gave it to the mother of the bride and said, “Mother, please give the dear bride to drink”.

Then, after I had already handed the cup to the mother of the bride, I suddenly remembered that she is a non-Jew. My instinct in that moment told me that taking back the cup of wine from the mother, resulting in embarrassing the mother, the bride, and everyone else was a serious matter. I reasoned, according to the best of my memory, that there is a position that holds that a non-Jew who is not an idolater does not render wine forbidden by touching it, even for drinking. On that basis, I went with the flow, did not take the cup back, and let the ceremony proceed normally.

Afterwards, I found that indeed Tosafot HaRid (Avodah Zarah 57a, s.v. “tinok“) holds that our wine touched by a non-Jew who is not an idolater is permissible even for drinking. But I did not find any other authority who shares this opinion, except for the lenient opinion of the Rema (Teshuvot HaRama 124), who goes to great lengths to defend those who are lenient regarding stam yaynam.

I very much hope not to repeat the same mistake; nonetheless, my question is did I act correctly in light of the desire to uphold human dignity (i.e., not to embarrass the mother, the bride, etc.)?

Thank you for the question. You did have one to rely on, as I will outline below. Still, even assuming that it was definitely stam yaynam, I think that to have acted otherwise would have been to embarrass someone publically. If there was ever a time to invoke the idea that kavod ha’briyot (human dignity) can override a derabanan (Berakhot 19b), it would be a case like this.

Not to mention that according to some (see for example, Netivot HaMishpat 234:3) a person does not have to do teshuva for an issur derabanan done b’shogeg (unintentionally). He reasons that since a derabanan is not intrinsically, metaphysically a davar assur (forbidden object), and its prohibited status derives from the obligation to listen to Chachamim in their takanot (edicts), thus a transgression b’shogeg is not a rejecting of the authority of Chazal. By this logic, you wouldn’t be being machshil (causing to sin) her either. I realize that this is a dangerous concept, and not one to bandy about, but as I said, we are dealing with embarrassing someone publically, so the principle that kavod ha’briyot can be docheh should definitely apply.

That’s assuming that there was no alternative to do it in a non-embarrassing way. Perhaps that wasn’t true. You could have “accidentally” slipped and spilled the wine and had to refill the cup, but of course that could’ve stained the bride’s dress (which would certainly be a hefsed merubah – but isn’t that why they use white wine), and certainly caused significant disruption, so still, this is not a small matter by any measure.

Regarding your question – yes there is a strong basis on which to rely, starting with Rema.

The first thing to note is that she did not touch the wine, only the cup. So it is negiah al yadei davar acher (indirect touch), and thus, according to Rema (Shulchan Arukh YD 124:24), the wine is permissible even not bimakom hefsed (in a case of fiancial loss). However, the Rema himself writes that this Halakha shouldn’t be publicized: