I don't know what else is in this thread other than that the OP deleted the whole thing of whatever this "definitive guide" was (LOL), but FYI Vietnamese is admittedly a bit tricky to master speaking in because it's tonal, but much easier to learn for understanding and literacy than many Asian languages, since you don't need to learn traditional Chinese characters (though the Cantonese readings of those do underly Vietnamese words), can just learn their Latin alphabet-based script with a few diacritic markers accessible through keyboard shortcuts, and the grammar's pretty simple.
I decided to stop going after Asian women (at least I think, LOL, that's the plan for now), but I love Asia still and am still aspiring to be a poor man's Arthur Waley of some sort if I have the opportunity and can stay alive, and Vietnamese may be my personal priority since it's a really wonderful country and I love the overlap with the Cantonese, so it's one of the languages I'm learning gradually even though I'm not planning to go there as an expat anytime soon (if ever).
So to make a long-story short, the language isn't necessarily easy, but certainly not impossible.