Final answer:
Benedick's statement, "Here's our own hands against our hearts," symbolizes that the love letters they have written are concrete evidence of their true feelings, revealing their genuine love despite their former denials.
Step-by-step explanation:
In the final scene of Shakespeare's Much Ado About Nothing, Beatrice and Benedick try to deny their feelings for each other, but ultimately fail to do so. Benedick's proclamation, "A miracle! Here's our own hands against our hearts," signifies that despite their attempts to conceal their love through wit and mockery, the love letters they have written reveal the truth of their deep affections. As Benedick utters these words, it becomes clear that their love for each other is undeniable, as tangible proof - in their own handwriting - contradicts their verbal denials. This moment signifies the overcoming of pride and the embracing of their mutual love.