You have hit exactly on it, KMR.
And what's most interesting about that is that I don't believe Barnabas was ever supposed to say "My love". If one looks closely at Depp, one can see that what we're actually being shown is the end of Barnabas saying "swear it" - right down to the exact same smile at the end. Apparently the "My love" was merely dubbed in the trailer to quickly establish the Barnabas/Josette relationship. And while it's probably the most blatant example, it isn't the only place in the trailer where words are dubbed that don't appear in the film and that weren't said in the footage that's accompanies the dub. But more on that once the 2012 DS Film Slideshow reaches the scene with the next example.
Very good, KMR!
The Depp/Burton Dark Shadows played in US theaters for at least 161 days/23 weeks!!
The Depp/Burton Dark Shadows is now out on DVD/Blu-ray!!