JW weddings do not have vows.
The 'repeat after me' part is not vows. It is simple the couple obeying what the speaker is saying by repeating after him. They are reciting the words. No different than actors reciting lines.
There is no feeling or romance in that. How can there be? The heart is not there.
They didn't practice the vows before hand to know what they are vowing.
JWs are not married, other than legally, because they have not vowed anything.