EXTRA ECCLESIA NULLA SALUS!
Pope John Paul II, in an address to the Franciscans, said: "Like Brother Francis we have to be conscious of and absorb this fundamental and revealed truth, contained in the phrase consecrated by tradition: "There is no salvation outside the Church."
Here is how the Church, as the infallible Voice of Christ, has seen fit to declare its doctrine* on salvation:
Ex Cathedra: ** There is but one universal Church of the faithful, outside of which no one at all is saved. (Pope Innocent III, the Fourth Lateran Council, 1215)
Ex Cathedra: We declare, say, define, and pronounce that it is absoulutely necessary for the salvation of every human creature to be subject to the Roman Pontiff. (Pope Boniface VIII, the Bull Unam Sanctam, 1302)
Ex Cathedra: The most Holy Roman Catholic Church firmly believes, professes, and preaches that none of those existing outside the Catholic Church, not only pagans, but also Jews and heretics and schismatics, can have a share in life eternal; but that they will go into the eternal fire which was prepared for the devil and his angels, unless before death they are joined with Her; and that so important is the unity of this ecclesiastical body that only those remaining within this unity can receive an eternal recompense for their fasts, their almsgivings, their other works of Christian piety and the duties of a Christian soldier. No one, let his almsgiving be as great as it may, no one, even if he pour out his blood for the name of Christ, can be saved, unless he remain within the bosom and the unity of the Catholic Church. (Pope Eugene IV, the Bull Cantate Domino, 1441)
*A doctrine or dogma of the Church is a truth which has been revealed by God and must be believed by all Catholics.
**When the Pope speaks Ex Cathedra, or "from the Chair" he has invoked his highest teaching authority. An Ex Cathedra pronouncement is a dogma that is absolutely immutable and unquestionable.
Sacramental Baptism is necessary for salvation:
Ex Cathedra: "If anyone says that Baptism is optional, that is, not necessary for salvation, let him be anathema!" (Council of Trent, Canon 5, Denainger 861)
Catechism: "….by Baptism, the gates of heaven, which sin had closed, are opened to us." (Catechism of the Council of Trent, #58)
Ex Cathedra: "All the faithful must profess only one baptism, which regenerates in Christ all the baptized, just as there is one God and one Faith." (Council of Vienne, 14th century)
Ex Cathedra: "If anyone says that true and natural water is not necessary in Baptism, and therefore interprets metaphorically the words of Our Lord Jesus Christ: 'Unless one be born again of water and the Holy Ghost…'; let him be anathema." (Council of Trent, Canon 2, Denainger 858)
(Thus it is wrong to hold a speculative theory that desire alone can save a person.)