Can a girl with short hair look pretty? Yes, she can.
If she had long beautiful hair, would she look even prettier? Yes, of course.
Why? because men are attracted to healthy beautiful young women. A woman's hair can enhance her beauty. Please note, that just because a girl's hair is long, that doesn't make her beautiful. There are also ugly women with long hair, and long hair that isn't attractive. Next time you want a beauty pageant, you'll notice that they all have long, well kept, healthy hair.