1. This sister’s repentance from zina should not lead her to despair of the mercy of Allah, for Satan will exploit this and will prevent her from repenting and doing good deeds. 2. It is wrong to say that the one who commits zina will be punished in this world and in the Hereafter even if he repents. There is no need to fear having deformed children and no need to be anxious. For more on how to repent from zina, please see the detailed answer.