Final answer:
John Newman did not find difficulty believing in transubstantiation due to his trust in Church authority and the tradition of the Church Fathers that supported this mystery of faith.
Step-by-step explanation:
According to John Henry Newman, as presented in Apologia Pro Vita Sua, he did not experience any difficulty in believing in the Catholic doctrine of transubstantiation because his view of the presence of Christ in the Eucharist was influenced by his understanding of Church authority and the Church Fathers.
For Newman, the tradition of the Church and the teachings of the early Christians provided a reliable basis on which to accept the mysteries of faith, even without the need for logical proof or empirical evidence. This intellectual and spiritual framework made the acceptance of transubstantiation, which proposes that during the Mass, bread and wine are changed into the Body and Blood of Christ, a matter not of difficulty but of faith aligned with the teachings of the Church.