Those who contemplate suicide, like I did many years ago, are caught up in four devastating feelings: illness, hurt, abandonment and doubt as they feel no hope of the future. If they do not have a relationship with Christ through that of a Spiritual rebirth, John 3:3-7, then they are already destined to go to the lake of fire as their names are not found in the Lambs book of Life and will come under Gods judgement.
Many Christians who are weak in faith also contemplate suicide when things get unbearable in their life because they become consumed with their problems leaning on their own understandings instead of leaning on God whom is their help in times of trouble. This allows Satan who comes to kill, steal and destroy prey on them and steal what little faith they have.
The question is, even if they have weak faith do they still go to Hell if they commit suicide? I think it is possible because they lost all faith and hope in God therefore leaving themselves void of God in their life, which would cause them to be separated from God as they turn from that faith which is Christ Jesus. We also have Gods commandment thou shall not kill. God will forgive a murder who repents, but where is repentance if you are dead and can no longer ask for it. It repented (having regretted) Judas that he sold out for that of riches and even though he gave the money back he went and hung himself, Matthew 27:3-5, instead of asking Jesus to forgive him instead.
We also have heard that our sins are forgiven past, present and future for Christ paid the price for all sin even though we fall short at times, but grace keeps us in that of Gods righteousness which is found in us and God knows the intents of our hearts. If one ask for forgiveness before they sin are they forgiven? Answer to that in my perspective would be why would one sin willingly knowing they are going to sin. Grace does not give us a license to sin.
God is the life giver and in Him are we made in His image. Who has that right to take away what God has given.
Psalms 33:18 Behold, the eye of the LORD is upon them that fear him, upon them that hope in his mercy;
Psalms 33:19 To deliver their soul from death, and to keep them alive in famine.
Psalms 33:20 Our soul waiteth for the LORD: he is our help and our shield.
Psalms 33:21 For our heart shall rejoice in him, because we have trusted in his holy name.
Psalms 33:22 Let thy mercy, O LORD, be upon us, according as we hope in
1Corinthians 6:19 What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own?
1Corinthians 6:20 For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.
Proverbs 3:1 My son, forget not my law; but let thine heart keep my commandments:
Proverbs 3:2 For length of days, and long life, and peace, shall they add to thee.
Proverbs 3:3 Let not mercy and truth forsake thee: bind them about thy neck; write them upon the table of thine heart:
Proverbs 3:4 So shalt thou find favour and good understanding in the sight of God and man.
Proverbs 3:5 Trust in the LORD with all thine heart; and lean not unto thine own understanding.
Proverbs 3:6 In all thy ways acknowledge him, and he shall direct thy paths.