Q: In the 1940 movie of Pride and Prejudice, the phrase “upon my word” is used repeatedly to mean “I can’t believe what I just heard.” How did those three words amount to a statement of incredulity?
A: It’s been a while since we saw the 1940 film of Pride and Prejudice, with Greer Garson and Laurence Olivier as Elizabeth and Darcy, but as we recall the screenplay took quite a few liberties with Jane Austen’s novel.
With that in mind, we searched for “upon my word” in two online versions of the novel, an 1894 edition from Ruskin House and a 1900 edition from Odhams Press, both published in London.
The expression appears eight times in each version, occasionally used in its original sense of an assurance of truth or good faith, but primarily in its later sense of an exclamation of surprise or strong emotion—the meaning you describe as incredulity.
In this example of the original sense from chapter 16, Elizabeth assures Wickham that she’d express her dislike of Darcy anywhere in Hertfordshire except at the house where he’s staying:
“ ‘Upon my word I say no more here than I might say in any house in the neighbourhood, except Netherfield.’ ”
And in this exclamatory example from chapter 29, Lady Catherine expresses surprise and annoyance at Elizabeth’s outspokenness:
“ ‘Upon my word,’ said her Ladyship, ‘you give your opinion very decidedly for so young a person.’ ”
When the usage appeared in the late 16th century (originally as “upon his word”), it was “an assertion, an affirmation, a declaration, an assurance; esp. as involving the veracity or good faith of the person who makes it,” according to the Oxford English Dictionary.
The first OED citation is from a guide to English language and culture: “Doth not Euripides saie & Phorphyrie vpon his word, that a bodie of presence is best worthie to rule?” (Elementarie, 1583, by Richard Mulcaster). Phorphyrie refers to the third-century philosopher Porphyry of Tyre.
And here’s the first “upon my word” version for this sense: “Madam, upon my word I will not rob you of your Jewel, I freely resign him to you” (from The Humorists: a Comedy, 1671, by the playwright and poet Thomas Shadwell).
The dictionary says the usage came to mean “assuredly, certainly, truly, indeed” in the late 16th century. The expression is “of my word” in the first Oxford example for this sense:
“Of my word, she is both crabbish, lumpish, and carping” (from Endimion, the Man in the Moone, 1591, a comedy by the Elizabethan playwright John Lyly).
The OED’s earliest “upon my word” version for this sense is from a report to the British Parliament in the mid-17th century about a rebellion in Ireland:
“Upon my word your Lordship is little beholding to him” (from A Declaration of the Commons Assembled in Parliament; Concerning the Rise and Progresse of the Grand Rebellion in Ireland, July 25, 1643).
In the early 18th century, the expression came to be “a simple exclamation of surprise or strong emotion,” a usage Oxford describes as “now somewhat archaic.”
The dictionary’s first citation, which we’ve expanded, is from The Beaux Stratagem (1707), a comedy by the English playwright George Farquhar:
“Lady Bountiful: Let me see your arm, sir — I must have some powder-sugar to stop the blood. — O me! an ugly gash; upon my word, sir, you must go into bed.”
As for now, standard dictionaries define “upon my word” variously as meaning indeed, really, assuredly, and as an exclamation of surprise or annoyance.
Merriam-Webste, for instance, defines it as “with my assurance: indeed, assuredly,” and gives this example: “upon my word, I’ve never heard of such a thing.”
And Cambridge says it’s “used to express surprise or to emphasize something.” The dictionary has an example from chapter 2 of Jane Austen’s Sense and Sensibility.
In this expanded version, Mr. Dashwood agrees with his wife that he doesn’t have to give his mother and her daughters three thousand pounds, as he originally planned, despite his late father’s request that he take care of them:
“ ‘Upon my word,’ said Mr. Dashwood, ‘I believe you are perfectly right. My father certainly could mean nothing more by his request to me than what you say. I clearly understand it now, and I will strictly fulfill my engagement by such acts of assistance and kindness to them as you have described.’ ”