So I have a Christian friend , I was talking about Buddhism to him then he asked the question if we are having rebirth , how did beginning of new birth start , he. Asked if there were 100 humans and they multiplied to 200 humans how did 100 new extra birth take place ,from where did the energy which formed their birth come from ? I know these are unanswerable questions and told him so , I even told him you should not think how it started but how to get out of the samsara , he said that there is no definite answer in Buddhism but in his religion he said that God created humans and that’s how it started . He said his religion had an answer

I told him about the 6 realms and we can go to any of the realms depending on our attachments. He said that Buddhist people don’t know where they will go after death which made him think Buddhism is scary .

As in his religion he said after death we go to heaven to rest eternally .

How can I give a good reply to these questions and how to make him think Buddhism is not scary ?

Thank for the advice in advance have a nice day .