Let's look at how Paris's words reveal personality. Let's also clarify what we mean by personality: character (integrity, values, beliefs), attitude, emotions, likes and dislikes, confidence and self-esteem, and other aspects I'm sure you could add.
When the Friar asks him why that Paris and Juliet are getting married so quickly, Paris says:
Now, sir, her father counts it dangerous
That she do give her sorrow so much sway,(10)
And in his wisdom hastes our marriage
To stop the inundation of her tears,
Which, too much minded by herself alone,
May be put from her by society.
Now do you know the reason of this haste.
Paris says he's following Lord Capulet's advice to rush the marriage because Juliet is so depressed over Tybalt's death. How would you characterize a person who decides to hurry into a marriage because his fiancee (who hasn't yet been wooed, even) is grieving? Would you say that Paris's actions were thoughtful, kind, considerate, and so forth? Or what other emotions and reasons might motivate him to agree to marry Juliet so quickly?
Keep in mind, Lord Capulet is a rich man, and therefore Juliet's dowry won't be paltry. Many young men in Elizabethan England married for wealth, since women were considered the property of their fathers and could help a man improve his station in life. Yet...Paris is a cousin of the Prince of Verona. Does he really need the money? So maybe it's not just purely financial, his reasons to move so fast....
Now look closely at scene 1, act 4, where Juliet and Paris have their first conversation of any great length in the entire play. So much is revealed about personality in a) words characters use with one another and b) how characters listen to one another.
Paris tells Juliet he is delighted to see her, calling her already "wife." Remember, we've never seen them speak to each other in any kind of romantic way to this point. What does this address to her tell us about him?
Juliet says, "That may be..." and calls him "sir." How is she feeling about her future husband?
Paris misses her point: that she is keeping her distance and saying, maybe we will be married. He doesn't hear her. He says,
That may be must be, love, on Thursday next.
He just switched her "may" to "must." What does that tell you about his confidence and his awareness of others? yet, he follows the line wih "love."
In film portrayals and stage portrayals, Paris is often shown as physically attacted to Juliet, clearly in admiration of her beauty. Do you find evidence to support this directorial interpretation?
A revealing statement comes later:
Do not deny to him that you love me.
He is telling Juliet, You know you love me.
Your reaction? How does Juliet respond to him? Note her dodging responses, full of subtext. Every line she says to him is full of doublespeak. And remember, her mission to the Friar is to make sure she can marry Romeo. Knowing the irony of this scene, Paris is rendered fairly foolish here, isn't he?
I suggest you study this exchange because you will learn a tremendous amount about the personality of a powerful young man who thinks he knows what is going on but is missing big clues.
When he learns of Juliet's death, he shows strong emotion.
Beguil'd, divorced, wronged, spited, slain!...
O love! O life! not life, but love in death!
Do his feelings appear sincere to you? Is he a man truly in love? How do you know? Note the words "beguil'd" and "spited." Who has beguiled or spited him?