I was watching an episode of The Golden Girls tonight. Blanche and Rose were having a bit of a fight over a, yes, a man, whom they both had feelings for. Blanche had found out that Rose had been courted by the same man and she suddenly said:
Oh, Rose, I can’t believe you would stab me in the back.
Does the following have a big difference in meaning?
Oh, Rose, I can’t believe you stabbed me in the back.
Technically these have two different meanings. In practice they would be interpreted by the listener in exactly the same way (in this context).
“Would stab me” means willing to, but didn’t necessarily do it.
“Stabbed me” means she did do it.
The two meanings are not mutually exclusive. They can both be true, and in this case they both really are true. But like I said, in practice they both have the same meaning. They both make the same point - that Blanche felt betrayed by Rose’s actions.