Great post, Sherzahd.
To add a note, I've never dabbled much in fantasy in terms of long stories, which sounds like something you are planning to write. Prophecies, if used correctly, can be an aid to a strong fantasy story - but the problem lies when the prophecy drives the story.
Your prophecy isn't BAD, per say, but it's quite direct. I already know a) There will be a princess of the Lascher line and she will be the last in her line b) She will become the first "bonded queen" which admittedly is a phrase I do not know yet without the context of your story, but I can easily assume it is some sort of power c) Her rule will be historical in the sense that "great changes" will come; I already know she's going to be special d) Some sort of religious figure will have chosen her; she is a divine choice and d) She will have either a tattoo of doves and flowers on her back, or that will be a metaphor.
See how much I know? I can already almost predict the plot - either a girl who doesn't know she's a princess will find out she's actually the last princess of her line, she'll become a special queen, bring about lots of changes because a God-figure has chosen her. Or, a princess will end up being the last in her line, become a special queen, yadda yadda yadda.
You want an air of mystery around your story. The prophecy should be less direct, I feel, for it to be powerful. I shouldn't know what at least half of the terms mean, and I definitely shouldn't be able to guess any major plot points. Additionally, I think rhyming would help here. I think a prophecy that is a bit muddled and confuses the reader - not too much, mind you, but enough - is much more powerful.
Down to the nitty gritty - note these are all personal opinions based on my writing style and if you write differently/disagree that's totally great.
I think your prophecy should have more flowery language. Think about it. This is kind of the one time that it's really allowed in writing. Go for it! Something that sounds cool instead of "cover," for instance: "Doves will spiral across her ashen flesh." You can change that adjective to match your character, flesh may sound too violent, and it may sound that she is dead, but I feel that will be more intriguing to your reader.
I mean, CS Lewis is a master, but a prophecy I've never forgotten from a fantasy book is the famous:
"Wrong will be right, when Aslan comes in sight,
At the sound of his roar, sorrows will be no more,
When he bares his teeth, winter meets its death,
And when he shakes his mane, we shall have spring again.
When Adam's flesh and Adam's bone,
Sits at Cair Paravel in throne,
The evil time will be over and done" (CS Lewis, Narnia)
The reason this is so memorable and powerful, to me, is because it's very vague. We don't know Aslan, we don't know what winter represents, Adam's flesh and Adam's bone could refer to any human, we don't know what Cair Paravel is nor why the throne is important. We do know there's a lion named Aslan and he's going to save everyone, but we know nothing of the who, when, why, or how.
Also, it rhymes. Kind of. It doesn't need to be a Walt Whitman level poem but it helps with the flow.
I'm sorry I couldn't help more, but i hope something I've said will be useful.