Laertes tells Ophelia that Hamlet's affection for her is false or unreliable in Act 1, scene 3 of Hamlet by William Shakespeare.
What are the three comparisons he makes in lines 5-10? What is a paraphrase of the similarities Laertes asserts between Hamlet's love and an early spring violet?
Laertes loves his sister, Ophelia, and in act I scene iii of Hamlet by William Shakespeare he warns her about getting too attached to Hamlet. His primary reason, of course, is that Hamlet will have to choose his wife based upon political or economic expediency because the future king's first love must be his country. Laertes goes on to give a few specifics about the apparently hot-blooded Hamlet who has been spending time with, and no doubt speaking words of love to, Ophelia.
The specific lines of warning you mention, as written by Shakespeare, are these:
For Hamlet and the trifling of his favor,Hold it a fashion and a toy in blood,A violet in the youth of primy nature,Forward, not permanent, sweet, not lasting,The perfume and suppliance of a minute.No more.
Though Shakespeare writes in English, he uses poetic, seventeenth-century English as well as some complex or contemporary (familiar at the time of the writing) imagery. Here is a paraphrased version of those lines:
As for Hamlet and the admiration he carelessly offers you,
Please don't consider it as anything more than a passing fancy, as changeable as fashion/style or as anything more than impulse or whim,
As a violet which appears early in the spring, before its proper time or season,
As something precocious and beautiful but short-lived (living only for a short season)
As the perfume which lasts for a moment, but then that moment passes away (thus it is "sweet, not lasting),
Nothing more than that.
Laertes is making four specific comparisons, things Ophelia would understand, to demonstrate how fleeting Hamlet's love for her is. One of them would have made his point; however, he offers one after the other, adding some weight to his argument and, he hopes, impressing his point home to Ophelia.
The first comparison is to fashion and style, something all women understand. What is "in" today can be "out" tomorrow, and if not tomorrow, the next day for sure (figuratively speaking, of course). Laertes claims this is exactly the kind of love Hamlet has for her.
The second comparison is similar to the first, which is no doubt why they are found in the same line. A "toy in blood" is just a passing fancy or feeling, something that is here one day and gone the next--much like the fashion imagery.
The third reference is to a violet that blooms too early in the season. While it is beautiful and kind of magical to see a beautiful flower when, say, there is still snow on the ground, it is not the right time or place for a violet to bloom and it cannot last.
Your analysis of the perfume reference is correct, that the scent is sweet for a short time but it does not last.
Each of these images is Laertes' way of telling his sister that Hamlet's love, if he has professed it to her, is not a mature, lasting love but a fleeting, ephemeral feeling which is sweet for a moment but soon gone.
It is an interesting thing to consider what prompts Laertes to speak this warning to Ophelia. Perhaps he has seen them together or heard of their relationship, but in any case he is interested in protecting his sister's heart and, later in his speech, her chastity. Whether he is right or wrong about Hamlet's feelings for Ophelia, his intentions seem admirable--or at least more admirable than his father's.