First, the verse quoted is not related to remarrying; rather, it is discussing whether the Neder has Hafarah. Rebbi Yehudah says that if she made a Neder which does not have Hafarah, that she is penalized by not being allowed to get remarried to him.

Rebbi Yehudah remains with his Re'ayah from the Givonim. He says that the reason why the Zekenim were not Matir the Shevu'ah is because it was a Neder she'Yad'u Bo Rabim. Tosfos writes that even though it was a Shevu'ah b'Ta'us, still -- if, generally, a Shevu'ah which is made b'Rabim has Hafarah -- there would be no Chilul Hash-m in being Over the Shevu'ah, for people would assume that he had been Matir it. But since, generally, such a Shevu'ah does not have Hafarah, there is a Chilul Hash-m if they are Over it. This is as the Chachamim say, that people will not know that the Shevu'ah was a Ta'us and will think that the Zekenim are violating the Shevu'ah.

D. Zupnik