Answer:
He refuses to sell Emily because he has malefic plans for her and knows that Northup will not contribute to these plans.
Step-by-step explanation:
Theophilus Freeman is a cruel, greedy and unscrupulous man, unlike Northup who shows himself as an honorable and kind man, even with slaves. Northup offers a price to buy Emily and her mother, preventing the two from being separated and allowing them to have a better life. However Theophilus Freeman refuses to sell, because he does not believe that slaves should be treated well and because he has other plans for Emily. He wants to sell her when she is older and when she is already a woman with a well developed body, so that she can be sold at a higher price to a man who has a desire for her.
The above question is about "Twelve Years a Slave." A book that takes place in 1841 and shows the sad reality of slaves and the inhuman ways they live. This book also addresses the danger of being a free Negro, the corruption of slavery, the fragility of slave women in relation to their masters, brutality, separation of families, among other themes.