It is, and it is a faith that never fails that God imparts to the one who hears the Gospel message and responds to it by trusting in The Faithful One, the Lord Jesus Christ, and a new spiritual babe is born in the heart of that person.
If the "faith" fails, if it is merely an intellectual acknowledgement and enthusiasm without the repentance of a convicted heart, it is not the one given by the Father, a spiritual birth has not taken place, the Comforter is not residing, and the power of sin still overtakes that person.
A prominent example is Charles Templeton, the pal of Billy Graham: Click (here) and (here). Here is an excerpt from the last:
"Templeton, as his own story makes plain (p. 3), never truly reached a point where he was intellectually convicted
of the truthfulness of Christianity (what the reformers called assensus). Assensus represents the conviction we
have in our minds. Assent of the mind is vital to our faith. Graham, according to this testimony, had enough
assensus to make a decision. He was not going to be an eternal “tire-kicker” with regard to Christianity.
Sure, he could have waited, like Templeton, until every possible
objection to the faith was answered, but this would amount to a failure of modernistic irrationality. We can never
have all our questions answered. At some point there must be a sufficiency in probability."
Templeton's "Christianity" was just in his head, but apparently never in his heart, so he remained lost to God by refusing the truth of God's Word. The conviction was not complete, nor repentance from sin.
It makes it easy to claim that one cannot lose their salvation because they never had it to lose.
Sorry; but I can't go down that road.