How can you assume it is the Catholic Church that is being deceived? Are YOU immune to deception? It is the Catholic Church that was founded by Jesus Christ starting with Peter over 2000 years ago. Every Protestant Church was started after the year 1500. One word about the rosary......it is not about Mary. The rosary is a meditation on the life of Christ. If all you think about is the prayer "Hail, Mary", you are not praying the rosary in the way it is intended.
May God bless you all.