Also, does it hook you? What could make it better? What should I change? Would you read on? All these questions should be considered. =]

Thank you.

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Devon and Kristen did everything together, from playing video games while enjoying pizza and soda, to chasing each other through the nature trail in the hot summer. And nothing could separate them. At least, that was what Devon always assured Kristen: “Krissy,” Devon said one night, while lying with her on a trampoline in his backyard, when they were ten, “I want you to know that nothin’ll ever come between us, kay?”
“You sure, Devon? Cause’ sometimes I wonder if we be friends as long you say.”
“I swear, Krissy, cuz your my strawberry short cake,” that was what Devon called her, because her hair was so red and pretty.
And Kristen had believed him, but then they got older. Everything changed after that.

I really like the unique voice of the characters in your dialogue. If you keep their dialogue in its colloquial context throughout the story, their voices are the kind of attention-grabbers which agents like. As for the opening before the dialogue, it suffers from wordiness and a lack of any goal I can care about. These two kids were best buds, but how does that translate into their current adult dilemma? Or goals? Now for the specific nits in parentheses:

Devon and Kristen did everything together, from playing video games while eating pizza and drinking soda into the wee hours of the morning (why not reduce the wordiness? Something like: “from playing video games while enjoying pizza and soda”),

to chasing each other through the nature trail in the hot summer. (I like this.)

And nothing could separate them. At least, that was what Devon always assured Kristen: “Krissy,” Devon had said one night, while they lied (lied?) on the trampling (trampoline) in his backyard, staring at the stars. (Re-work this sentence and break it up. You have interrupted what Devon told Kristen by injecting a lot of unnecessary back story)

This was so long ago, too, before they even knew what life was about, back when they were about ten years old. (It is implied that 10-year-olds don’t yet know what life is all about, so you can drop this explanation) “I want you to know dat nothin’ll ever come tween’ us, kay’?”
“You sure, Devon? Cause’ sometime I wonda if we be friends as long you say.” (Nice.)

XD: I suggest you open with the dialogue and then get right to the dilemma that drives this story. Right now, I’m only guessing at what that conflict or dilemma is.

Here is the thing about rules: as children we think they are unbreakable, unstopable, solid. When you get older you start to realize they are sometimes unenforcable. And in writing, they are more like strong suggestions. Because if there was a formula ("Follow these rules and you'll put out a good book") there would be one book in the world and it wouldn't be worth reading after a while. The rule about not opening with dialogue is flimsy. Some of the best books and best authors open with dialogue. Here are a couple that jump to mind right away:

Ender's Game by Orson Scott Card

Beyond World's End by Mercedes Lackey and Rosemary Edghill

Roll of Thunder Hear My Cry by Mildred D. Taylor

(The last one on the list is the one that makes me think of the dialogue style in your story, though all three are very good examples.)

That being said, I think I see a hook here: the idea that these people are making promises at an age too young to understand just how hard it might be to keep them. It's setting up for heartache and I feel for them. Heartache is one of those univeral experiences that people have to go through in their lives. So this feels like a "lessons in life, lessons in love" kind of story. That's what I'm getting anyway.

I have to disagree with the unique dialog though. I found it distracting and pulled me out of the story rather than pulled me in it because I had to start sounding out the words invidiually to get the meaning, like reading my kindergartener's writing. (hapee brtay gramu) If you want to keep the sound just through in a few. Such as "I want you to know that nothin'll ever come between' us, kay?" It keeps the sound but is a little easier to read. The last one works except for "wonda". I would just keep it wonder to help with readability. Try not to mess with the spelling as much as possible.

quote:

---

"Hey! How's it going?"

"Oh, okay. How about you?"

"I'm doing great. Just got fired."

"Cool! So now, what?"

---

Now, using "said" and other such words (notice the punctuation):

quote:

---

"Hey!" Susan said, "How's it going?"

"Oh, okay. How about you?" John asked.

"I'm doing great," Susan answered, "Just got fired."

"Cool!" John said, "So now, what?"

---

And now with "action tags" (again, notice the punctuation)

quote:

---

"Hey!" Susan slapped John on the back as she passed him in the hall at school. "How's it going?"

"Oh, okay." John shrugged. "How about you?"

"I'm doing great." Susan turned to her locker. "Just got fired."

"Cool!" John leaned up against the locker next to hers. "So now, what?"

---

Two things that I either missed before or are new. This line:

"At least, that was what Devon always assured Kristen: “Krissy,” Devon said one night, while lying with her on a trampoline in his backyard, when they were ten,"

I'd write it without the colon. Like this:

At least that was what Devon always assured her.
"Krissy," he said one night when they were ten, lying with her on the trampoline in his back yard, "I want you to know that nothin' will ever come between us, kay?"

I changed a few things around that were awkward to read and cut a word that wasn't needed due to the comma. You also use names repeatedly and I think the lines would be stronger if you used "he" and "she" a few times. The reason I removed the comma in this version is because it makes you pause and feels a little like a run-on sentence. It's especially awkward in dialogue.

The other part I'd change is this:

"“I swear, Krissy, cuz your my strawberry short cake,” that was what Devon called her, because her hair was so red and pretty.
And Kristen had believed him, but then they got older. Everything changed after that."

The part where you feel the need to give her a nickname and then explain it is a litte bit of an insult to your reader. Most girls that are nicknamed Strawberry Shortcake have red hair. It's not really necessarry to explain that. But I'd go one step further and say that you need to pick a name for her and stick with it. In thirteen lines, you have managed to give this poor girl three names. Also, the second to last line is clunky. Why not try:

And Kristen believed him. But then they got older. Everything changed after that.

I know commas are supposed to give the reader a spot to pause, but I feel like you need something more dramatic than a comma. A period works a little better in this case I think. That gives the last line that "Dun dun duuuun!" feeling.