Michael Quinion at the excellent World Wide Words shows evidence - see Believe you me - that English has an archaic VSO form used for imperatives, as in the King James Version of the Bible
For thus saith the Lord unto the house of Israel, Seek ye me, and ye shall live
but mentions that "Believe you me" is an outlier that came into the language late.
For further help here, I turned to Benjamin Zimmer, at the University of Pennsylvania, an ace at researching historical word usage. He tells me that there are earlier examples, but that nearly all of them are in verse, where the phrasing is useful for scansion. He has been able to find only three examples in prose from the nineteenth century.
What seems to have happened is that a once-standard phrase that had been lurking in the language for generations suddenly became much more popular and widespread around the 1920s. What we have here is a revitalised fossil, a semi-invented anachronism
It's amazing how access to sources has blossomed since that was written in 2006. Google Books now finds dozens of prose hits from the 19th century:
- "Well, then, believe you me, that all poor Biddy's hope rests on her sweet Saviour" - 1829
- "Master Denis shall feel, believe you me, what it is..." - 1829
- "and believe you me, before that day twelvemonth it. would take more nor a yard of tape to make them an apron-string" - 1834
- "it involves misery for themselves and for their children, believe you me the same selfish instincts that prompt these men..." - 1839
- "The work is God's, and not man's; and believe you me, that not only Annas and Caiaphas, but Herod and Pilate too, are against Luther" - 1840
- "Well, sir, believe you me, I'll give that lassy as good a strapping as ever she got when she comes back" - 1841
- "for, believe you me, I'll never look at the same side of the road with Tade Ferrall again" - 1842.
- "But believe you me, they will not be able to proceed much further" - 1847
- "No, no, believe you me, sir, it won't do in a free country" - 1857
- "Helter-skelter, pell-mell down the staircase they flew, and, believe you me, the commodore helped them in their descent" - 1861
- "Believe you me, that if you were blown down there you'd be bruised to mummy among the tombstones" - 1864
- "But many a time, believe you me, I bought a rabbit from you" - 1870
- "Balzac stands for Paris, believe you me" - 1877
- "We've not come to the worst yet, believe you me" - 1877
- "Believe you me, they wouldn't have done the like of that without they'd got their orders direct from the Castle" - 1878
- "No, Mike, believe you me, while grass grows or water runs" - 1882
- etc ...
The interesting observation is, at first glance, that the majority of these early examples come from Irish publications: The Christian examiner and Church of Ireland magazine, Sketches in Erris and Tyrawly, The Dublin University Magazine, the Irish novel In Re Garland: A Tale of a Transition Time, Michael Banim's The Town of the Cascades, and so on. This could explain why "believe you me" is an outlier by date. A hypothesis: perhaps it isn't a relic of the archaic English VSO construct, but arrived by a different route. Irish Gaelic is a VSO language; maybe its sentence pattern influenced Irish English? A quick Google suggests "Believe you me" might correspond to the Irish phrase "Creid uaim é!" = "Take it from me!" (literally, "believe from-me it").
The 1857 example, by the way, isn't Irish, but Charles Dickens editorial in Household Words magazine.