Quote 4
Had Edward been intentionally deceiving her? Had he feigned a regard for her which he did not feel? Was his engagement to Lucy an engagement of the heart? No; whatever it might once have been, she could not believe it such at present. His affection was all her own. She could not be deceived in that. Her mother, sisters, Fanny, all had been conscious of his regard for her at Norland; it was not an illusion of her own vanity. He certainly loved her. What a softener of the heart was this persuasion! How much could it not tempt her to forgive! He had been blameable, highly blameable, in remaining at Norland after he felt her influence over him to be more than it ought to be. In that, he could not be defended; but if he had injured her, how much more had he injured himself! If her case were pitiable, his was hopeless. His imprudence had made her miserable for a while; but it seemed to have deprived himself of all chance of ever being otherwise. She might in time regain tranquillity; but he, what had he to look forward to? Could he ever be tolerably happy with Lucy Steele? could he, were his affection for herself out of the question, with his integrity, his delicacy, and well-informed mind, be satisfied with a wife like her -- illiterate, artful, and selfish? (23.1)
Poor, poor Elinor. She realizes that love should truly be a match of equals – and that Lucy Steele is certainly not Edward's equal (obviously, she herself is).
Quote 5
"I do not understand you," replied he, colouring. "Reserved! -- how, in what manner? What am I to tell you? What can you suppose?"
Elinor looked surprised at his emotion, but trying to laugh off the subject, she said to him, "Do not you know my sister well enough to understand what she means? Do not you know that she calls every one reserved who does not talk as fast, and admire what she admires as rapturously as herself?" (17.7)
Edward's communication problems emerge rather awkwardly here – he's surprised and perhaps ashamed by the idea that other people find his reticent nature notable. However, he's clearly uncomfortable and unsure of how to remedy this. We're not sure what exactly he'd say if he could come out and say whatever's on his mind, like Marianne.
Quote 6
"Me!" returned Elinor in some confusion; "indeed, Marianne, I have nothing to tell."
"Nor I," answered Marianne with energy, "our situations then are alike. We have neither of us anything to tell; you, because you do not communicate, and I, because I conceal nothing." (27.17)
The difference in Elinor and Marianne couldn't be made more plain – their different tactics on communication are clearly both flawed.