Greetings in the precious Name of our Lord and Saviour, Jesus Christ.
Thank you for your letter and for your question as to why we believe Jesus went to hell.
The Apostles Creed states: "I believe in God the Father Almighty… and in Jesus Christ, His only Son our Lord, who was conceived by the Holy Spirit, born of the virgin Mary, suffered under Pontius Pilate, was crucified, He died and was buried. He descended into Hell. The third day He rose again from the dead…"