Okay I'll try to put these all in one reply
The Love You Give
Alright this one is nice and short, only 2 sentences. Good for you . I do think it could use a little more detail, saying exactly what the "encounter" is. Since it doesn't seem like we're at that part yet (all we have right now is that they keep noticing each other), I'll leave that part for you to write.
It's possible to even remove some details from this blurb. The first sentence can simply just be "Akiro has a crush on Hinata," though if Delinquent x Good Girl is the kinda vibe you wanna advertise then you can leave that in.
Miracle Teardrops
This blurb is pretty good and short, though I do believe it could use some edits to sound more interesting.
Alexa is a girl with a rare illness. After being given two flowers that bloomed from a mysterious boy's tears, she begins to find some hope. Is this the work of miracle teardrops?
I feel like "illness" gives off a more serious and dire connotation, though that's up to you if you wanna change it. The rest of the changes were just stuff that I felt would sound more natural. Though keep in mind that's just my East Coast USA type of thinking with words, and I can't assume where you're from so I don't know if it's any different where you're at. Just try to sound as natural as possible as if you were presenting this story to a group of people.
That Beautiful Melody
Ah common mistake I see in blurbs: too vague. Focus on setting the mood in the story itself, not the blurb.
This basically seems to be a story about a girl who can't chose between two love interests. Let's make that the blurb.
It's springtime, and Tomoyo has a secret crush on her classmate, Ryu. That is, until someone else comes into her sights.
Since you have a very short comic with an easy to follow plot, adding a little vagueness can work to make it tempting to read. With this rewrite, you get an idea of what's going on without saying too much.
Waiting Under the Stars
I'd remove "This story is based on true events." It might make people feel like they're just gonna read an autobiography, but even then I don't think it helps all that much in getting people to read the story. Other than that, I think this does it pretty well, though I do recommend mentioning a key event to get people interested in at least reading up until that event. Talk about when they meet again.