sister, did you read my post? I just told you the difference. A Muslims believes, but doesn't necessarily try to be pious. A Mu'min is pious. So the example of a Muslim would be someone who believes that God is one, and believes in Islam. But he doesn't pray except in Ramadan, doesn't give zakah, does a lot of sins, doesn't read Qur'an regularly etc... A Mu'min has more taqwa, and does righteous deeds while refraining from evil ones. Every Mu'min is a Muslim, but not every Muslim a true Mu'min.