BENEDICK
Then is courtesy a turncoat. But it is certain
I am loved of all ladies, only you excepted; and
I would I could find in my heart that I had not a
hard heart, for truly I love none.
BEATRICE
A dear happiness to women! They would
else have been troubled with a pernicious suitor. I
thank God and my cold blood, I am of your humor
for that. I had rather hear my dog bark at a crow
than a man swear he loves me. (1.1.122-130)
Note that both Beatrice and Benedick say they’ll never love anyone. This little spar is likely saying "of course we’ll never love each other." Invulnerability to falling in love is a point of pride for them both.
BENEDICK
That I neither feel how she should be loved
nor know how she should be worthy is the opinion
that fire cannot melt out of me. I will die in it at the
stake.
DON PEDRO
Thou wast ever an obstinate heretic in the
despite of beauty. (1.1.226-231)
Benedick hates love, and he’s known for hating beauty. Beauty can’t move him to love, but perhaps some more meaningful trait in a girl (like how witty she is, and if she’s named Beatrice) could move him.
BENEDICK
I do much wonder that one man, seeing how much
another man is a fool when he dedicates his behaviors
to love, will, after he hath laughed at such
shallow follies in others, become the argument of
his own scorn by falling in love—and such a man is
Claudio. (2.3.8-13)
It’s poetic justice that Benedick means to deride Claudio with this speech, but knowing what we know about Benedick a few acts from now, Benedick could very well be describing himself.