Sentence:  Dear Kate, take a fellow of plain and uncoined constancy; for he perforce must do thee right, because he hath not the gift to woo in other places: ... a speaker is but a <WSD>"prater</WSD>"; a rhyme is but a ballad. A good leg will fall; a straight back will stoop; a black beard will turn white; a curled pate will grow bald; a fair face will wither; a full eye will wax hollow: but a good heart, Kate, is the sun and the moon. 
Meaning of the word marked with <WSD> tags:  A person who prates; a chatterer.