Only what people do matters. So people who don't believe in God can be beautiful human beings who are helpful and polite, just like how people who do believe in God can be impolite and selfish. (Note the "can". It all depends on the person, not on his/her beliefs.)

his deads and works

rup he bhahyarup asun, manushyache karyacha vichar kela pahije

Nothing can proove the person is good and gentil because we have not the total ability to see what is inside the mind of that person. the other side is so relative to you..if that person suits you or not, for what he could be good and gentil to you and with you.. Religion exist to correct people not to give them graduations or certifications give them all time they will show their secrets..