Jeez.
There have been numerous times in my life where I am absolutely 100% confident that I have heard something, only to be wrong. Similarly there have been times I've said something that has been completely misheard by another, who was adamant they heard something different to what I actually...
I think Bong is 100% sure of what he heard. He could still be wrong though.
There's certainly been times I've been sure I've heard one thing but it transpired to be something else.