The sentence "I may never meet you again in my next life" contains rich emotions, which can be told to different people, but different people tell you and reply in different ways. For example, when a friend says this to you, he is expressing your support and help. At this time, you can reply, "Let's cherish the friendship in this life!" .
But if a lover or relative says this to you, you can reply, "Let's love each other in this life and cherish the fate together!" .