Student or Learner
'You cannot love him, Estella.You would never marry him?'
Why not you will never marry him?
Using "will" makes the statement a certain prediction, and this may seem to more presumptive, as well, on the part of the speaker, though either way, with or without "will" the statement is presumptive. It's just more presumptive with "will"
You would never marry even if he had a billion dollars. You know he's not right for you at all.
If he weren't rich, would you still marry him? You could be setting him up for a huge disappointment. But you don't care about that, do you? You just want money. Right?