Well is such a deliciously flexible word. Laertes could be meaning any number of things in using it. It could be a way to say all is well – the ancient Danish way to say, “It’s all good.” Or it could be a way to say “fine” – both the sarcastic and the sincere versions of that flexible word.
It could also express a kind of resignation – a sense of “whatever.” Or it could just be a placeholder – a non-response response to just get back to fighting.
The Hamlet Project 