Pertelote wants her man to be a man. She wishes to disgard the dream simply as a dream with no meaning. She even suggests that poor indigestion has actually caused his dream.
"Now you have lost my heart, lost all my love.
I cannot love a coward, that I swear!"
Chanticleer obviously has more at stake; the dream foreshadows his demise. Chanticleer counters by showing numerous stories throughout history where dreams were ignored and people died.
"...To wind up, let me say just this to you:
To me this dream portends adversity."
Of course, it's Chanticleer's love for Pertelote that eventually guides his decision to ignore the dream.
"When I look on the beauty of your face,
And see those scarlet circles round your eyes,
Then all the terror that affrights me dies."