Query Critique #10

QUERY #10 - Natasha

Dear, Agent
Dear Ms. Agent, 

If seventeen-year-old Sharlet Gales had known she was dating the son of the devil, she might have reconsidered.
Nice opening hook. I also like the unique spelling of your MC's name. 
 

After being stalked by him for weeks, Sharlet finally meets Kalav Devilson when she threatens to kill him with the tip of her mascara pen. Nevertheless, she can’t go through with it because he’s just the thing she needs to add some excitement in her life. And before she knows it, he turns her world upside down. No, literally—the trees hung down from the sky while they walked on top of the stars. They fall in love.

I like most of this, but I recommend cutting "They fall in love." We infer it from the "world upside down" thing.  BTW, most cliché phrases don't belong in queries, but, when you play off them like you did, they can work. I've also tightened a few phrases to eliminate the passive voice and past tense.

After Kalav Devilson stalks her for weeks, Sharlet threatens to kill him with the tip of her mascara pen. Nevertheless, she can’t go through with it--he’s just the thing she needs to add some excitement in her life. Before she knows it, he turns her world upside down. No, literally--the trees hang down from the sky while they walk on top of the stars. 

Kalav admits that he doesn’t want to be evil and promises to change. But after her best friend finds out that that he is carrying out his father's agenda, Sharlet learns that she may not have known Kalav as well as she thought. Unfortunately, Satan doesn't like the changes Sharlet is trying to push on Kalav and kidnaps him, hoping to lure her into Hell so he can dispose of her. Although she is livid with Kalav, Sharlet falls for Satan’s trap, and finds herself navigating through Hell—a world with mermaids, deserts made of honeycomb, and carbonated lakes. The thing is, everything beautiful here has its evils.
I like the fresh take on Hell, and YA readers can relate to an MC whose boyfriend's parent doesn't approve.  :) Watch your verb tenses--try to keep your query in present tense. I also cut the best friend--she's just mentioned here to get the info to Sharlet. I also made an assumption on the reason Satan needs to lure Sharlet to Hell (rather than just having her hit by a bus in the real world or something)--please correct me if I'm wrong.  You don't need to mention that she falls for his trap--if he hopes to lure her to Hell and she ends up there, it's assumed.   

Kalav admits that he doesn’t want to be evil and promises to change. But after she finds out that he's still carrying out his father's agenda, Sharlet learns that she may not know Kalav as well as she thinks. Unfortunately, Satan doesn't like the changes Sharlet is trying to push on Kalav. He brings Kalav to Hell, hoping to lure Sharlet to follow so he can dispose of her in his own domain. Sharlet finds herself navigating through Hell--a world with mermaids, deserts made of honeycomb, and carbonated lakes. It's surprisingly beautiful--but everything here has its evils.

Sharlet believes Kalav can rise above his birthright. If he doesn't, however, she'll be a prisoner of hell for eternity—and the world will be taken over by the Anti-Christ. Sharlet's problem? Love might not actually be enough for him to change.
Make sure you consistently capitalize Hell. I'm also a bit confused--is Kalav the Anti-Christ? I made an assumption here, as well. (I've made a CORRECTION, since it was the wrong assumption). I'm also going back and forth on the sentence fragment "Sharlet's problem?" 
Ah, heck.  Let's leave it in--it adds voice.   
Sharlet believes Kalav can rise above his birthright. If he doesn't, however, she'll be a prisoner of Hell for eternity--and Kalav will become the Anti-Christ and take over the world. and the Anti-Christ will take over the world.

Sharlet's problem? Love might not be enough for him to change.

AMETHYST is a YA paranormal romance novel complete at 70,000 words.

Thank you for your consideration.