Safek whether a woman bentched (bonus true story at the end)

There is an unresolved safek in the gemara in berachos by if women are chayav midioraisa or midarabanan in benching. A nafka minah in this is that if a woman isn’t sure whether she bentched, what should she do? If her chiyuv is dioraisa, she should bentch since its safek dioraisa l’chumrah. if rabanan, l’hakhel. However, it’s also a berachah that is a dioraisa, so there is an intersection of a berachah, which in safek is l’hakhel, and a dioraisa, which is l’chumrah in safek scenario. Therefore, there is a sfek sfeikah. So what should a girl do?

True story behind the Question: I was asked this question last week on a shidduch. I told the girl that there is a safek over what a woman’s chiyuv is in bentching, and therefore she shouldn’t, because there are many rayahs brought in the aruch hashulchan around o.c. 187, for example, why their chiyuv is dirabanan. Because she was modern, that wasn’t a good feminist answer, so I had to impress her with my epic halachic knowledge 🙂 and told her how rabbi akiva eiger says women can make kiddush and motzi men, and that this gemara strictly applies to bentching, while dagul mirvava disagrees.