God can make the sinner holy.. The author of the Letter to the Hebrews calls Christians “holy brothers, sharing in a heavenly calling” (Hebrews 3:1) Paul calls us “priestly people, holy people, God’s chosen people.”
And not only Christians, I think. In the “Honor Roll” of Biblical heroes recorded in Hebrews, there are other examples. For instance (Hebrews 11:7)it says that the obedient and faithful Noah “inherited the righteousness that comes through faith.”
But we all are sinners, even Mary, just like God says in Scripture, right?