What would be the best portrait lens for my Nikon D3100?

My choices are 85mm f/3.5G ED VR or 50 mm f/ 1.4 or Nikon 85mm f/1.4D AF Nikkor Lens?
What is ED stands for and what is the difference between f/3.5G ED and f/1.4D on the 85 mm?
I'm about to make a purchase and don't know which one is best if I'm going for great portrait and outdoor natures. I like the effects of the blurred background very much and I know all three of these lenses will do the trick right?

The f/ number is the maximum aperture. The smaller that number, the easier and better the background blur. If you don't know this stuff you should sign up for a basic photography class.

For blurred backgrounds, the best would be one of the f/1.4 lenses. As for focal length, it would be totally up to you whichever feels more comfortable for you to use. At 50mm, you would be close to your subject when getting head portraits. At 85mm, you'd be too far to get whole bodies. Generally the shorter lens would be more adaptable.

The best portrait lens to use on a D3100 is the AF-S 50 mm f/1.4, since it is a medium telephoto lens and used by many portrait photographers.

The 85 mm lens is best used on a full frame dSLR or 35 mm SLR camera for shooting portraits for the same reason.

Make sure that any lens you buy for your fine D3100 is a AF-S lens, so it will auto-focus on your D3100

ED is what Nikon calls their high end lenses with Extra-low dispersion lens elements in it

http://www.nikonusa.com/...Glass.html

First off., the D lenses won't autofocus on your camera. You need lenses with AF-S in their name, which means that the lens will bring its own autofocus motor.

So i think you should strike the 85mm/1.4D and the 50mm/1.4D from the list of candidates. There's a 50mm/1.4G which has AF-S, you might consider that one, and that's also the one that i'd recommend for your purposes.

There's a 85mm/1.4G AF-S, but that one is another $500 more expensive.

The 85mm/3.5G is an interesting case… It's actually a macro lens, and it'll be tack sharp already wide open, thus at least offsetting the closer maximum aperture a bit. It also comes with VR, which is nice to have. It's certainly usable as a portrait lens, but you won't get as shallow DoF/blurred background as with the 50mm/1.4G, and it's a tad long. On the other hand, you get a full fledged macro lens for free in addition to your portrait lens with it. Still, for dedicated portrait shooting i'd recommend the 50mm/1.4G.

Another lens to consider would be the 60mm/2.8G. It's a bit of an intermediate between the 50mm/1.4G and the 85mm/3.5G. It too is known to be a good portrait lens - it's fully usable wide open, unlike the 50mm/1.4 which needs to be stopped down a bit to achieve maximum sharpness. So unless you specifically want either a soft look, absolutely minimum DoF or shoot in low light, there's little practical difference between the two. Furthermore it too is a macro lens and you can take proper macro shots with it in addition to portrait use. So for outdoor nature shots - flower closeups and such, it would be a nice choice. It's too short for shooting living insects though, which would be scared away as you have to get really close to them with it.

Now there's also the new Nikkor AF-S 85mm f/1.4G

http://www.cameralabs.com/reviews/Nikon_Nikkor_AF-S_85mm_f1-4G/

Practical Photography recently reviewed the Sigma 85mm f/1.4 and they couldnt praise it enough. I would seriously put this on your consideration list too.

For portraits f/1.4 is going to be far more useful than f/3.5, especially with the "blurred background effect" you'd like to produce.

(A little read up on aperture and depth of field would help you understand this a little better).