How others will see it. The Beguiled is not recommended for family viewing. It's not a date movie either. It has unpleasant moments. It will fascinate many, however, because there are a number of interesting themes present.
How I felt about it. Lincoln supposedly said, "You may fool all of the people some of the time; you can even fool some of the people all of the time; but you can't fool all of the people all of the time." Or in other words, a leopard can't change its spots. The naive staff of the school want to be fooled. They would like to believe that the handsome young man can be turned into a peaceful farmer, or better yet, a faithful lover. Of all the women at the school, only two can see him for what he is all along, a Damn Yankee, and they're practically left out of the story.
But let's discuss Eastwood's character first. His motivation is self-interest. If he charms the school staff, he can wait out the war in comfort. He might even get to have sex. If he selects Geraldine Page despite the presence of two younger, attractive, and more easily manipulated women, he will have it made. If he focuses solely on Edwina (Elizabeth Hartman), the second in command, he will have a strong ally, and can still survive the way.
But Eastwood has a beast inside him. He can't resist the temptation of seducing all women who take an interest in him, which in the closed environment of the boarding house is the romantic equivalent of selling more than 100% ownership of a corporation. Especially dangerous is the hottest and horniest young woman, Carol (Jo Ann Harris), whose heart is as black as Eastwood's, even though she lacks criminal intent. He knows she will ruin his cozy set-up, but the evil inside him is too strong. His fate is sealed when his hateful words toward the staff alienate him from Page, the woman who controls his fate.
Page's character is more complex than that of Eastwood. Her principal concern is for the school itself, both now and in the future. During Eastwood's rise and fall, she progressively seems him as a victim, an unwanted guest, a potential farmhand, a potential lover, a troublesome burden, and finally as a predator who must be put down. Throughout this process of enlightenment, Page continues to try to keep the students united under her leadership. Her will to turn her charges into young ladies is admirable, given the difficulties of her situation.
Edwina and Carol are simply love-starved. They fall into the "fooled all of the time" category, because his companionship is of greater value than his character. Amy, the innocent child, plays a different role. The world is black and white for her. Either you're good, or you're evil. Once she moves Eastwood into the latter category, she's secretly delighted to participate in the headmistress' revenge. But like any good girl, she won't do so unless she's asked to do so by her parent substitute, Page.