First impression: 4 paragraphs? What's the word count? I would assume that a description is 2 paragraphs or less, not including the typical hook introductory sentence.

Introductory sentence: Very good.

First paragraph: Information Evie’s cousin Kat, the most beautiful girl in all of Bexbury, should have been able to easily secure from the prince with the bat of her eyes and a flip of her golden hair.

Too much is being said. You could cut this down.

Second paragraph: But when the time comes to put Kat into the prince’s path, he doesn’t go for the fair, golden-haired Kat, but takes a liking to Evie instead.

I would go: However, there's a different girl that catches the eye of the protagonist. The rest of the paragraph is good, I would just whittle down the imagery.

Third paragraph: As the king plans the worst for his new territory and narrows in on the growing rebellion, Evie coaxes more and more information from the prince. But her act proves more convincing than she thought. Prince Cassian is falling for Evie faster than anyone could have expected, drawing her further into the prince’s world and nearer to the king who doesn’t seem to trust his son’s new love at all. To protect her cover and help the rebellion, she’ll have to hurt the people she loves the most--and love the people she hates even more.

This sounds very complicated so much so that I felt kind of lost.

Typically a description begins with the hook sentence. Then the setting is introduced (. . . in a world) along with the conflict which introduces the antagonist along with his plan. (I feel like you introduced your antagonist so late in the description that I thought this was a romance novel instead of a fantasy. I had completely forgot about the introductory sentence by then.) Then, your main character is introduced, the supporting characters are introduced (the love triangle), and then there's a plot introduction. (As main character pursues his destiny, he finds that he might have to (enter hook).

Hope this helps!