good picture, looks like you could use a little proof reading though.

Could you point me some of the flaws you see? English is not my first language, so it´s always a little hard to see any mistakes ^^U

This is how I would put it. I'd like to be able to show you where I made the changes. but that would take a lot of work on my part.
Now this copy isn't perfect. I'm not a writer, and I'm sure that if you let someone else look at your draft they would have other changes that I missed. When you are writing its always good to get a second or third or even fourth opinion.

"So, When are you gonna let me take you out on a date?" Gunter asked.
"You're Kaila's Boyfriend. I can't do that to her." Nadine replied feeling uncomfortable about the situation. The truth was she had been in love with Gunter since she was twelve, and now there he was asking her out on a date.
"She's okay with it." He said, snapping Nadine out of her thoughts. "We Talked about it last night after having sex" He added Grinning at her.
Nadine blushed as a small spark of hope lit her heart. She had been friends with Kaila since preschool. She could never hide her attraction to Gunter from her, and she knew Kaila would never approve of something like that. "Liar!" Nadine Scolded him feeling outraged at his nerve.
"One day, I'm going to take you out on a date." Gunter responded with a smirk on his face.
"Please leave, you jerk." She replied "I will never go on a date with you." She said, doing here best to keep her voice down. After all, She was tending a flower shop and it is bad business to scare the customers away.

"Had been", always had problems with that XD
Thanks, that looks quite better than my text, mind if I change it and credit you at the submission?
I´ll try to get a second opinion also, but all the people who could help me here speak spanish ^^U

Not a problem. I don't mind I'm glad I could help.