What is best for portrait 50mm 1.8G or 1.4G?

I'm really confused of whether I should get a Nikkor 50mm 1.8G or 1.4G, the difference in price is huge, and I want to know does the 1.4 worth this price difference? I was going to get the 1.8 but I heard that the 1.4 is much better, is that true?
I'm getting the lens for portrait photography mainly ( including wedding photography ) .

also, is there's difference in Low Light Performance between the two of them?

Added (1). I forgot to mention that I'm a beginner, I'm amateur photographer.

If you are asking this, then you are not a good photographer. This question is like photography 101. Smaller number for the aperture means wide opening and more light. That means better low light performance. Shooting wider also means very narrow depth of field and better bokeh. I rarely shoot 50mm for portraits. I work with 70mm at least.

Oh, I'm impressed with eyeofjake already. What a rude answer!

I will assume that you do not have a full format camera, since you are new at this. Eyeofjake says that he uses a 70mm for portraits. Since he is a perfeshional, I will assume that he does have a FF camera and 70mm is decent for portraits with that format. Actually 85mm is the "classic" focal length for FF portrait work, so maybe eyeofjake doesn't know as much as he wants us to think he does. 85 is pretty much the standard for portraits.

THE THING IS…

Your camera has a "crop factor" or magnification of 1.5X, which makes a 50mm lens act like a 75mm lens would on a FF camera. This makes a 50mm lens very desirable fro portraits on cameras like a Nikon D3000, D3100, D3200, D5000, D5100, D7000, or D300s.

There isn't a TON of difference between the appearance of an f/1.4 lens and an f/1.8 lens, so buy the f/1.8 lens and you will be very happy with the results on your camera.