Kumano is generally considered a very safe destination for solo female travelers. Japanese people are known for their politeness and respect towards others. Crime rates are low and the locals are often ready to help visitors. Most areas, including Kumano, have accessible public transportation which is safe and reliable. It's common to see solo female travelers exploring the beautiful Kumano area without fear. You need to consider common safety precautions such as not leaving belongings unattended, particularly cash and valuable items, but overall, the area is very safe.