The question implies that before we 'die', we are 'alive'; that there is some change of circumstances. So, what is 'being alive'? Let us take the answer: it is a state of consciousness. Then I define, for the time being, death to be that event when consciousness ceases.
Everybody knows they will die, but is there life afterwards? I cannot prove anything on paper; all I can do is to suggest that one opens up completely in mind, heart and body - the answer should be revealed, if at all, more easily this way. My answer is: yes. There is immense literature on this, but I stress again that words can only point in the direction of the true answer. However, one question which springs to mind, which indicates the affirmative to many including myself, is:
"If not, then what is the purpose of life?"Thus, I assume that there is some life after death.
Is this life and all possible further existences of an everlasting period or does there come a time when we really do 'kick the bucket' for good? Suppose the latter, i.e. the sum total of our lives is finite. Then I would regard these lives as just one life, broken up by a number of interruptions (deaths). I ask a second time, "What is the purpose of such a life?"
Henceforth, I assert that there is always life after death. What then is the nature of life after death? Before I respond to this, I need to indicate my approach ...