It depends. I think many of us are thinking of the following scenario.
W: Dear Fiance, I love you very much and know that you probably expect me to take your name when married, but, I’ve been thinking about it a lot recently, and it would really mean a lot to me if I kept my own name, at least to some extent. You see (insert reasons for wanting to keep own name). Can we think about doing something like this seeing as it would honestly mean the world to me? I just can’t imagine leaving my name name behind.
M: What!!! You want to keep your own name instead of taking mine? Never! Take my name or the marriage is off!!!
In which case it is pretty obvious which of the two is unprepared for marriage. I can understand a man saying that this tradition means a lot to him, even so much so that he can’t imagine getting married with someone who refuses to take his name. but if someone claims outright that under no circumstances would they marry a woman who didn’t take their name, something is wrong.