A nice guy who is someone who will repeatedly tell the girl of his wanting that is is kind and respectful of her feelings. In reality he is the opposite. He is only doing this to get you defences down. Nice guy will repeatedly try to get into your pants, or throw a fit if you don't do what he wants. If you were to ever call him out on his immature behavior he would look shocked and say "I'm a nice guy I wouldn't do that." I nice guy doesn't want to be your friend, he doesn't want anything other then for you to be his girlfriend so he wouldn't have to feel bad about himself. Most NICE GUYS are selfish creepy jerks, who don't know what I just want to be friends, mean.
Remember Guys: Nice guys don't need to remind people that they are nice and respectful. Telling people that your a nice guy is pretty much like someone saying no offence but....
NICE GUY:*leans in for a kiss*
Girl: What are you doing. I said thought that we were just friends.
NICE GUY: But I'm a nice guy, I'm not going to hurt you.
Girl: Dude? Seriously? A nice guy doesn't need to remind the girl his with that he is a nice guy. Please leave.