There is a sense in which the whole play is dogged by Lear's incredible lack of understanding of his daughters. Cordelia's truthful response of "I love your Majesty / According to my bond, no more nor less" is noteworthy in comparison with the flowery, exaggerated and completely insincere declarations of love from Regan and Goneril, and yet Lear wants his pride flattered and the love his daughters have for him to be overt and public. The way in which he turns on the one true daughter who loves on him and surrenders himself into the hands of Regan and Goneril indicates his own foolishness.
However, having given away his authority to Regan and Goneril, he then goes on to see how his daughters only squander that power and bring his kingdom into a state of chaos. Appearance and reality have been confused by Lear, but it is only towards the end of the play that he is able to recognise how true Cordelia has been towards him, raising an army to save him from her sisters. Note Cordelia's words as she is finally reunited with her father in Act IV scene 7:
Thy medicine on my lips, and let this kiss
Repair those violent harms that my two sisters
Have in thy reverence made!
Cordelia is a character who is explicitly linked therefore with reconciliation and restoration. Just as with her sisters, her true attitudes expose themselves during the course of the play and Lear comes to realise which of his daughters he can really trust.