I have nothing but the greatest respect for R’ Hershel Schachter, but I’m not aware of anywhere in SH”A or any other Halachic writings that would indicate that a Rav has the ability to issue a binding psak Halacha that two particular people *must* get married. This may have been taken out of context, or this may be R’ Hershel Schachter’s personal opinion that goes against the conventionally excepted wisdom of most Poskim.
Either way, I second LU:
I think it would be very problematic for anyone to walk away from this thread with the conclusion that a Rabbi can order them to marry someone whom they don’t want to marry.