What are Claudio's thoughts and feelings after Hero unveils herself in the final scene of Shakespeare's Much Ado About Nothing?

We can gain a better understanding of Claudio's thoughts
and feelings the moment Hero unveils herself in the final scene by first looking at what
we know of his thoughts and feelings prior to this
scene.

We know that one thing Claudio was feeling at the
moment just before the unveiling was a deep sense of grief and repentance. We begin to
see Claudio's repentance portrayed the moment Borachio confesses that, by Don John's
urging, he had tricked Claudio into believing that Hero was Margaret and that she was
unfaithful. Claudio calls Borachio's confession "poison," referring to how his
confession has just killed his soul like poison, as we see in his line, "I have drunk
poison whiles he uttered it" (V.i.234). Claudio also exclaims "Sweet Hero" and proclaims
that now he is seeing her as the pure woman he fell in love with, which he regrets
because it is too late, as we see in his lines, "[N]ow thy image doth appear in the rare
semblance that I loved it first" (239-240). He also begs Leonato to revenge himself for
Hero's death by any means Leonato sees fit (261-263). Not only that, Claudio writes an
epitaph to hang on Hero's tomb proclaiming her innocence and her wrongful death, and he
begs forgiveness of the goddess Diana, a goddess known for her virginity (V.iii.3-11,
12-13).

Since we see how deeply grieved Claudio has become over Hero's
death and how deeply repentant he has become, we know that when who is actually Hero is
unveiled, he will feel a profound sense of joy and relief. Also, we know from Claudio's
line after Hero is unveiled, "Another Hero!" that he feels the same thing Hero does. He
feels that the Hero he unjustly slandered and violated has been reborn anew, fresh, and
undefiled. Hero expresses this sentiment best when she says, "One Hero died defiled; but
I do live, / And surely as I live, I am a maid" (V.iv.65-66).

Hence,
we know that due to his profound sense of grief and repentance, when Hero is unveiled
before Claudio, he feels a profound sense of joy and relief. We also know he feels that
she has been born anew, undefiled, and pure, just as Hero declares herself to
be.