Apparently you don't understand my facts completely and here is where you are confused. Even though this shallow ground hearer in Luke 8:13 is said to have "believed," yet he is never said to have been "saved." How do we know that the shallow ground hearer was never actually "saved"? First, his heart condition is
contrasted with that of the
"good ground" hearer in the 4th soil, who's heart was
"good" and
"honest." Thus, his heart was
not good, being like the soil to which it corresponds, being "shallow" or "rocky," lacking sufficient depth. Such soil represents a sinner not properly prepared in heart.
People who "believe" in a shallow way and rejoice at the preaching of the gospel without a prepared heart, and
without a good and honest heart, and without having "root" in themselves, do not experience real salvation. So not all belief is the same.
Unlike saving belief, temporary, shallow temporary belief that has no root, produces no fruit and withers away is
not rooted in a regenerate heart. How can
no depth of earth, no root, no moisture, no fruit, represent saving belief? (Matthew 13:21-22; Mark 4:5,6,16,17; Luke 8:6,13) It doesn't. Faith without works is dead. Also the same Greek word for believe "pisteuo" is used in
James 2:19, in which we read that the demons believe "mental assent" that "there is one God," but they are not saved. The demons
do not believe in the Lord Jesus Christ (Acts 16:31) and are not saved. Same Greek word "pisteuo" in Acts 16:31 as well.
John has portrayed people who "believe" (at least to some extent) but are clearly not saved. There is a stage in the progress of belief in Jesus that "falls short of firmly rooted and established belief" resulting in salvation. As we see in
John 2:23-25, in which their belief was
superficial in nature and Jesus would not entrust/commit Himself to them.
Also, in
John 8:31-59, where the Jews who were said to have "believed in him" turn out to be
slaves to sin, indifferent to the words of Jesus’, children of the devil, liars, accused Jesus of having a demon and were guilty of setting out to stone and kill the one they have professed to believe in. We can see at best that these Jews merely believed in Him (based on their own misconceptions and expectations) of Jesus, yet upon gaining further knowledge about Jesus through His words, we see they did not truly "believe unto salvation," but were instead children of the devil.