As much as I despise giving other stories a single star, I feel like I have to with this one, and I truly hope you do not take any offense.
The way I see it (and correct me if I am wrong), it appears like you tried to tie in a personal, real-life experience or emotion into this story, which I do not fault you for doing in the slightest; I try to do the same with mine. However, it is very bland. There isn't really a driving plot to it other than "her" wishing for "him" not to leave her side while she sleeps. It, along with many other ordinary ideas, could have potential if it were thought out more. For example, you could have shined light on issues that would make the story more interesting, such as:
Why is she scared of him leaving her?
What makes her think he will let go of her to begin with?
HOW did she build up this "shield" in her heart?
To me, at least, adding these questions and answering them (or leaving them up to interpretation, but the questions still need to have some glimmer of light shown on them) would have made for a slightly more improved story.
Furthermore, the way in which you wrote it confused me quite a bit. When someone speaks, what they say are typically surrounded by quotation marks. Rather than writing , Him-Pink promise!, you should have instead said, "Pinky promise," he answered. It makes it so much easier to read, to me at least.
Overall, the story just lacks a lot, as mentioned prior. Am I saying you are a bad writer? Of course not! Everyone who creates and publishes their works on this site has the ability to become a great story-teller. You just need to work a lot more on it.
I wish you the best of luck on your future works, and I hope to see some improvement!