One new characteristic we see Juliet gain in Act 3, Scene 2, in which Nurse informs her of Tybalt's death, is the ability to doubt and distrust.
Juliet's first response is to feel that she has been deceived by Romeo. We see this in her speech beginning at line 76, in which she calls Romeo a series of contrasting images, such as "beautiful tyrant" and "fiend angelical." All of these oxymorons serve to question Romeo's character, arguing that he is not as wonderful as she first saw him to be. She even ends this speech with, "O, that deceit should dwell / In such a gorgeous palace!" solidifying her feelings of having been deceived by Romeo.
However, her next response is to argue that she should not "speak ill of him that is my husband." In other words, she returns to her initial faith in him and her adoration. She justifies Tybalt's murder by arguing that Tybalt was killed because he would have killed Romeo. While learning to distrust Romeo is a new characteristic, it is Juliet's ability to reason that leads her to the conclusion that her distrust is unjustified. Her ability to reason is not a new characteristic. We see it in the balcony scene in which she justifies her love of Romeo by reasoning that his name is meaningless. While her reason is not a new characteristic, it does lead her to trust Romeo in a whole new and stronger way. Her trust is stronger now that Romeo's character has been called into question. Hence, this newborn trust is an additional characteristic that we witness Juliet gain in this scene.
Therefore, in terms of transformation, Juliet seems to gain two characteristics in this scene: the ability to doubt and the ability to trust despite doubt.