The Yuan Dynasty did not allow Mongolian women to marry Han Chinese, because if they did, the relationship between Han Chinese and Mongolian ancients would not be very good, and there were so many uprisings at the end of the Yuan Dynasty. Zhu Yuanzhang was also afraid that Mongolia would come back again, so he ordered people to build many military forts on the border. Zhu Yuanzhang did this in order to consolidate his regime, so he said that these policies were also aimed at preventing the Mongols from making a comeback and destroying their regime.
In order to better combine Mongolian women with Chinese culture, Zhu Yuanzhang did not slaughter them wantonly, but encouraged them to marry Han Chinese. In this case, Zhu Yuanzhang abolished the adoption marriage system in Yuan Dynasty, and Mongolians adopted it. For example, after the death of their father, they will inherit, and in another case, after the death of their brother, their younger brother will inherit all their widows, which is ethical for the Han people.
Generally speaking, Zhu Yuanzhang, while winning the hearts of the Han people, criticized some systems of the Yuan Dynasty for treating other ethnic groups indiscriminately, which is very classic. It is also a blessing for Mongolian women who have integrated into the Han nationality, so it is understandable to feel cruel from the national point of view.