You say you will die someday, but how do you know it? Do you know what death is? Do you have any experience of death? No, you will say you have seen others die, and so you infer that you too will die someday. But suppose we arrange things, and it is quite possible, that a certain person is not allowed to see any other person die. Can he know on his own that he is ever going to die? He cannot. So it is just your conjecture, based on external evidence, that you will die in some future. There is no internal evidence, no intrinsic source of knowledge within you which can sustain your conjecture that you will die. That is why a strange thing happens, that in spite of so many deaths taking place all around, no one really believes that he is going to die; he believes while others will die he is going to live. Your innermost being knows no birth and no death; it is eternal. You only know that you are.
Raman asks you not to guess, but find out for yourself if there is really birth and death. You have no inner evidence in support of birth and death; the only dependable evidence available within you says, “I am.”
I too, say to you there is every evidence that makes you know, “I am.” And if you go still deeper you will know, “I am not.” Then you will know only a state of “am-ness” within you.