Define “faith.” What is the content of Catholic “faith” that one must have along with participating in the sacraments for Catholics to be saved?
It’s obviously different for different age levels. But let’s assume adult with normal mental capabilities - in normal U.S. circumstances:.
Faith in existence of one Triune God. (Three Persons in One God - Father, Son and Holy Spirit)
Faith in attributes (eg. omnipotent) and activities (eg. creation) ascribed to God
Faith that Second Person of the Trinity became man (Jesus) to redeem us and save us from our sins. That He was conceived in the Virgin Mary by the power of the Holy Spirit. That He was crucified, died, and rose again on the third day. That He ascended into heaven and will come again to judge the living and the dead.
Faith that Jesus established His Church on the rock of Peter. Faith in the teachings His Church puts forward as true.
Faith that Jesus established sacraments to communicate His supernatural life (sanctifying grace) to us.
Faith in the need to be obedient to God if we wish to retain this new life in us.
Faith in the existence of the eternal states of heaven and hell.
Faith that after death we will be judged by Our Lord and spend eternity in one of those two states.
Those are the “bare bones”.
Now, the Church does not teach that a normal adult absolutely cannot be saved unless and until they have professed faith in all those teachings. If someone who was studying the faith because of a desire to love Our Lord, do His will, etc. were to die, we teach there is a high likelihood they would go to heaven. (They would be considered as having received a “baptism of desire”. The Church also teaches a “baptism of blood”.)
I am presuming when you say “to be saved”, you are referring to that initial reception of grace in the sacrament of Baptism. If you mean “saved” in the sense of spending eternity in heaven, then it is necessary to live so that we die in that state of grace.
We believe that deliberately sinning in a serious matter and not repenting is a rejection of God (rejection of Him as God, the One who has authority over us, to tell what we must do, what is right and wrong…). When we reject/separate ourselves from Him, we separate ourselves from His supernatural life of grace.