The true Church holds to the core beliefs of Christianity without subtracting or adding to them. Christ is the eternal God come in the flesh, there is one God and 3 distinct identities (persons) who exist simultaneously as the One God. The virgin conception, the sinfulness of man and the need of a savior, the new birth, the Gospel which is the death burial and physical resurrection, the 2nd coming, baptism, eternal mediator and priesthood of Christ, the priesthood of all believers, the infallibility and inerrancy of Scripture, judgment and rewards to the believers. These are the essentials that are clarified in the Scriptures.
If the Church one attends does not hold to these essential beliefs, they are not Christ's Church no matter what name they have on their outside or on paper. This is not my opinion, but the Bibles explanation what the apostles taught through the Gospels, the book of Acts, and in the Epistles.
In conclusion there is one true Church, but it is not found in a certain denomination or group by itself. Those who claim you must join their group or Church to be right with God, only prove they do not understand what the word Church or body of Christ means. It is not exclusive but inclusive, as it is found in the heart of all those who have accepted the true Jesus, and have come to God the way He has provided (through His son on the cross), and hold to the essentials of the faith. Whether one is Lutheran, Anglican, Baptist, Presbyterian, Episcopalian, Charismatic, or Pentecostal, etc. The Church transcends denominational barriers, it exists within denominations, as well as outside of them. This is the Universal Church that has continued from the beginning of Pentecost. While denominations may have differences on peripheral issues, they do hold to the core beliefs that make them all part of the body of Christ, the Chruch.