Could you plz explain what this sentence means in the context?

"We make our decisions based on any given time."
The context is as follows.

James: I've always liked you. Do you believe in fate?
Liz: I do.
James: So this is how its supposed to be?
Liz: We make our decisions based on any given time.
James: Well then... another time. (and he's leaving.)

(James has been secretly in love with Liz, but Liz loves another man.
and now James is trying to say goodbye to her just before he's leaving the country. he has to go away because of his certain situation and doesn't know when he could be back. )

I'd like to know the meaning of the sentence, "We make our decisions based on any given time." in this context.
Please explain it in plain English. Thank you very much in advance.