You must believe that Jesus Christ is God Almighty who took on flesh.
John 8:24, 58
24 I said therefore unto you, that ye shall die in your sins: for if ye believe not that I am he, ye shall die in your sins.
58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I AM.
28 And Thomas answered and said unto him, My Lord and my God.
29 Jesus saith unto him, Thomas, because thou hast seen me, thou hast believed: blessed are they that have not seen, and yet have believed.
That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
1 Corinthians 12:3
Wherefore I give you to understand, that no man speaking by the Spirit of God calleth Jesus accursed: and that no man can say that Jesus is the Lord, but by the Holy Ghost.
You must believe in what Jesus Christ did. The Lord Jesus Christ shed His holy blood on the cross as the payment for ours sins, He was buried, and rose again the third day.
15 So, as much as in me is, I am ready to preach the gospel to you that are at Rome also.
16 For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek.
17 For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.
1 Corinthians 15:1-4
1 Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand;
2 By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.
3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
4 And that he was buried, and that he rose again the third day according to the scriptures:
21 But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets;
22 Even the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe: for there is no difference:
23 For all have sinned, and come short of the glory of God;
24 Being justified freely by his grace through the redemption that is in Christ Jesus:
25 Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;
26 To declare, I say, at this time his righteousness: that he might be just, and the justifier of him which believeth in Jesus.
Finally you must believe what Jesus Christ has promised – everlasting life just by faith in Him.
14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up:
15 That whosoever believeth in him should not perish, but have eternal life.
16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
Verily, verily, I say unto you, He that believeth on me hath everlasting life.
25 Jesus said unto her, I am the resurrection, and the life: he that believeth in me, though he were dead, yet shall he live:
26 And whosoever liveth and believeth in me shall never die. Believest thou this?
Finally anyone who is trying to earn salvation by works or merit, their faith does not count toward salvation. They must stop trying to earn salvation to be saved. You must believe that you are a sinner (ungodly) and there is no other way to pay for sins except by faith the shed blood of Jesus Christ as the payment fro your sins.
But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.