Martha: Richard, how much longer are you gonna drag your heels before you tell Beckett how you feel? And I mean while she is awake, not lying on the ground with a bullet in her chest.
Castle: You don't understand...
Martha: It's complicated, so you say. Only it's not. It's not. Nobody's tomorrows are guaranteed, right? Wouldn't it be better to tell her even if the timing is wrong than never to tell her at all?
Castle: And what if she isn't ready?
Martha: Then she never will be. Then you move on.