Answer:
he thinks that opinionated persons tend to become prideful and thoughtless of others' feelings.
Step-by-step explanation:
In the poem "A Prayer for My Daughter", W. B Yeats wants his daughter to "think opinions are accursed" because he thinks that opinionated persons tend to become prideful and thoughtless of others' feelings.
Yeats relates this emotion with the past experience he had with Maud Gonne whom he loved so dearly. Maud was a strongly opinionated woman and she rejected him several times.
This might have differed if he had a son because he only feels that women who are opinioniated and beautiful are inconsiderate of others' feeling.