Yes, as the Bible says, no person is able to keep the law perfectly, and it is to be expected that our flesh is always going to fight against God's Spirit!
God was pleased with Solomon at first, because he saw that Solomon had at least some sincerity in wanting to please God. But he never left spiritual babyhood to go into full spiritual maturity, because he willingly chose the things of this life above that of pleasing God. So as in the Sower parable - Solomon eventually gave into the temptations of this life fully - which stamped God out of his life completely!
Yes, God will judge every person's "works" in the judgement! God knows how tell apart those who have fully become His own, and those who have not! And having some sincerity in serving God is a right direction to take on the road of salvation. But it requires prayer and persistence to become strong in the Lord (Ephesians 6) to where there is no longer a danger of falling away. God doesn't tolerate half-heartedness in the end, though he has to tolerate some of it for a time until a person grows past that stage (that is, if he does - not all do - due to lack of eagerness). He disciplines His children to help train them towards becoming fully wholehearted and obedient.
Heb 12:6-8
6 For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth.
7 If ye endure chastening, God dealeth with you as with sons; for what son is he whom the father chasteneth not?
8 But if ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons.
KJV
God was pleased with Solomon at first, because he saw that Solomon had at least some sincerity in wanting to please God. But he never left spiritual babyhood to go into full spiritual maturity, because he willingly chose the things of this life above that of pleasing God. So as in the Sower parable - Solomon eventually gave into the temptations of this life fully - which stamped God out of his life completely!
Yes, God will judge every person's "works" in the judgement! God knows how tell apart those who have fully become His own, and those who have not! And having some sincerity in serving God is a right direction to take on the road of salvation. But it requires prayer and persistence to become strong in the Lord (Ephesians 6) to where there is no longer a danger of falling away. God doesn't tolerate half-heartedness in the end, though he has to tolerate some of it for a time until a person grows past that stage (that is, if he does - not all do - due to lack of eagerness). He disciplines His children to help train them towards becoming fully wholehearted and obedient.
Heb 12:6-8
6 For whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth.
7 If ye endure chastening, God dealeth with you as with sons; for what son is he whom the father chasteneth not?
8 But if ye be without chastisement, whereof all are partakers, then are ye bastards, and not sons.
KJV