The epigraph comes from The PowerBook, a novel by Jeannette Winterson (born 1959) first published in the year 2000. Winterson has been a novelist (and essayist) to read and follow since three of her earliest novels: Oranges Are Not the Only Fruit, The Passion and Sexing the Cherry (author page at Amazon.co.uk, author page at Amazon.com). Her work (most often compared to that of Virginia Woolf, especially the Woolf of Orlando) arouses strong passions and in my experience never fails to fire the reader's imagination. I recommend her website and the rest of her work as the ideal introduction.
As with other epigraphs in Kiss, the very act of quotation gives Winterson's original sentence a change of context. First, the sentence:
There is no love that does not pierce the hands and feet.The context, in The PowerBook, is a description of love as a force larger and more powerful than individual subjectivity, psychology, can account for. For better or worse, its context in A Kiss Before You Leave Me (and in the rest of this post) is subjective, as a result of the proximity of both (a) a particular epigraph from Plato (which we'll talk about another day) and (b) the final chapter of Kiss.
It's a sentence that, even taken in isolation, provokes strong feelings, depending in part on (a) the reader's experiences of (and approach to) love and (b) the reader's interpretation of the sentence. From time to time I've tweeted each of the epigraphs to Kiss at least once, but this is the only one that ever triggered a strong negative response.
At first glance, the sentence (there on the screen, say, of your ebook reader, at the beginning of the last section of Kiss) does not appear to be ambiguous. There are clearly possible nuances of interpretation (just try to paraphrase it: how rational or how 'Romantic' do you want to make it?; do you want to highlight or tone down the allusion to Christ-like/Christian martyrdom?; etc.)--but it appears to say something like the following: to love another person (or group, or creature, or thing) is to be vulnerable to suffering terribly, like a martyr.
article in Wikipedia, the presentation here). The bad news is that I'm barred from spelling out the ambiguity of the sentence. It's something that has to fall into place for the reader.
It's not difficult. It doesn't rest on a syntactic ambiguity. It's not richly satisfying, especially for readers who don't yet know A Kiss Before You Leave Me. But seeing the ambiguity (which I can't spell out) and knowing just one thing about ambiguity (which I can)--can put you well on the way to knowing what to make of the end of the novel.
All you have to know about ambiguity--this sort of ambiguity in art or fiction--is that your task, as a viewer or reader, is not to resolve the ambiguity. Not to find some hidden sense (to be sought out) behind some manifest one (to be discarded). It's not an either-or but a both-and... to be embraced and experienced... and understood on its own terms.
Don't take my word for it. Look again at the drawing 'All Is Vanity': we aren't fully seeing it until we see it both ways. Or work through the whole theory of the Necker cube and the lengths to which viewers go to reduce ambiguity: the price they pay. Or read Shoshana Felman's extraordinary study of ambiguity in The Turn of the Screw (here, or included here).
All this may give you a clearer sense of how you deal with ambiguity, and what your options are....