The answer is: Didn't want to spoil inheritance

Ruth 4:5-6

In this poignant narrative, the kinsman, often called a "redeemer," has a tough decision to make regarding Ruth, the widow of a relative. His reluctance opens a fascinating window into the intersection of duty and family legacy in ancient Israel. By refusing to marry Ruth, he’s worried that doing so might complicate his own inheritance. Essentially, if he embraced Ruth and they had children, those children could inherit part of his estate, which could lead to the dilution of his own family assets.

But wait! History and cultural practices surrounding this Kinsman Redeemer concept provide vibrant depth to this story. The essence lies in the custom called **Leverite marriage**, which was aimed at preserving the family line—honoring the dead and ensuring one's name lived on. It gives a backdrop for understanding Ruth's loyalty and determination. She was a Moabite, a foreigner in Israel, yet she showcased remarkable fidelity and courage by following her mother-in-law, Naomi, back to Bethlehem.

Also intriguing is how this tale resonates with themes from earlier texts. For instance, think of justice in socio-economic contexts; lending a keen ear here reveals how the Israelite society emphasized a robust system to support widows, among society's most vulnerable. In choosing not to marry Ruth, the kinsman might symbolize an individualistic approach ultimately striving for personal gain, contrasting with the communal ethos champions in the Hebrew Scriptures. That switch in priorities lets us ponder how wealth and family might interfere with taking the right path of caring for others.