He would trust the assembled crowd. (If he were to think he was marrying one woman,
while the bride present was actually another woman, that marriage would be invalid.)
Gemara asks the question (suma heiach muttar b’ishto, uvnei adam heiach muttarin l’neshoseihen balayla) and answers tevias eina d’kala, i.e. voice recognition
I think his question was a legitimate follow up to the gemara that says blind people get married with tevias ayin of kol, and a deaf person can not hear and recognize that kol, how would he manage?
The marriage itself wouldn’t be the problem. The problem would be the potential violation of issurim down the road if one can not identify the person he/she is with.
If one must have sight or sound recognition of their spouse for them to
be permitted to each other, how does a blind deaf person get married?
It’s a logical question.
The unveiling of the Kallah is not only for the Choson. The Eidei Kiddushin must also get a good look at the Kallah or their eidus is not valid. How can they be mayid that Plonis bas Ploni is married to Chaim Yankle Plonawitz if they don’t know what Plonis looks like?