There is a logical reason for our belief in the Assumption of Mary. She was kept free from original sin by her Immaculate Conception. Death is a historical punishment for original sin. Since both Jesus and Mary were not guilty of sin, and thus free from the punishments of sin, they needed not to die. Nevertheless, they both embraced death to destroy the power and result of death and make it now a source of resurrected new life. Another personal note is that the year in which I was ordained was a special Marian year, commemorating the hundredth anniversary of the Immaculate Conception solemnly defined in 1854.
Notice the parallel between the life of Jesus and the life of Mary. Jesus was conceived virginally. Even though Mary was conceived by normal human intercourse, she was conceived in her souls free from original sin (feast day December 8th.). She was present at the death of Jesus and participated in a unique way with Jesus through her intercession in our redemption from sin and eternal death. Jesus ascended into heaven by His own divine power. Mary was taken (assumed) into heaven by Jesus’ divine power. This feast is a call to thank the Lord for His divine plan in calling us with Mary in future participation, both soul and body, in the eternal joys of God’s heavenly kingdom.