Never judge a book by its cover

Never judge a book by its cover. Moreover, never judge anyone by their appearances. Allah chooses who he wishes to guide, not you or I, for Allah says:

وَالَّذِينَ كَذَّبُوا بِآيَاتِنَا صُمٌّ وَبُكْمٌ فِي الظُّلُمَاتِ ۗ مَن يَشَإِ اللَّـهُ يُضْلِلْـهُ وَمَن يَشَأْ يَجْعَلْهُ عَلَىٰ صِرَاطٍ مُّسْتَقِيمٍ
[سورة الأنعام:٣٩]

But those who deny Our verses are deaf and dumb within darknesses. Whomever Allah wills - He leaves astray; and whomever He wills - He puts him on a straight path
[6:39]