If it was that easy to be saved from hell then we wouldn't have scriptures such as Matthew 7:13-14 that warn us that few people will be saved.
James 2:19 KJB
"Thou believest that there is one God; thou doest well: the devils also believe, and tremble. "
James 2:13-26 KJB
"13 For he shall have judgment without mercy, that hath shewed no mercy; and mercy rejoiceth against judgment.
14 What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him?
15 If a brother or sister be naked, and destitute of daily food,
16 And one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit?
17 Even so faith, if it hath not works, is dead, being alone.
18 Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works.
19 Thou believest that there is one God; thou doest well: the devils also believe, and tremble.
20 But wilt thou know, O vain man, that faith without works is dead?
21 Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar?
22 Seest thou how faith wrought with his works, and by works was faith made perfect?
23 And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness: and he was called the Friend of God.
24 Ye see then how that by works a man is justified, and not by faith only.
25 Likewise also was not Rahab the harlot justified by works, when she had received the messengers, and had sent them out another way?
26 For as the body without the spirit is dead, so faith without works is dead also."
Matthew 7:13-14 KJB
"13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it."