1 Thessalonians 4:[13] But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope.

God wants us to know. God doesn’t want us to worry our hearts and minds with the fate of our loved ones who have died.
There is no hope for those who die outside of Christ. Those who have not been born again and have not trusted Jesus as their Savior. But we who have trusted Jesus have hope.

[14] For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.

The source of our hope is the death and resurrection of Jesus Christ. If this is not your source then you are one of the ones who will sorrow with no hope.

We have the hope of REST. Those who have died in Christ are at rest. They are no longer in pain or suffering but are at rest.
The Bible says in Hebrews:
Hebrews 4:[9] There remaineth therefore a rest to the people of God.
[10] For he that is entered into his rest, he also hath ceased from his own works, as God did from his.

[15] For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.

The words I am giving to you are the words of the Lord. This is not some wish but a promise from God to those who trust in Him.

[16a] For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God:

We also have the hope of RETURN. Jesus Christ is coming back.
Jesus said in John 14:
John.14:[1] Let not your heart be troubled: ye believe in God, believe also in me.
[2] In my Father’s house are many mansions: if it were not so, I would have told you. I go to prepare a place for you.
[3] And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also.

16b and the dead in Christ shall rise first:

We have the hope of Rest, the hope of RETURN, and we also have the hope of RESURRECTION.
When we go to our rest we go with the knowledge that there is still life after death.

[17a] Then we which are alive and remain shall be caught up

We also have the hope of REDEMPTION. Jesus Christ is going to deliver us from this world of trouble. He has bought us with His blood and promised to come back and claim His purchased possession.

[17b together with them in the clouds,

We also have the hope of REUNION. Those who have passed with their faith in Christ will be reunited with those of us who have also trusted in Christ and what a glorious reunion that will be.

[17c to meet the Lord in the air: and so shall we ever be with the Lord.

We also have the hope of eternal REWARD. We have the promise we will spend eternity in the presence of the Lord. What greater expectation can a man have?

[18] Wherefore comfort one another with these words.

If your faith is in Christ you have hope. If you do not have Christ in you then you are indeed without hope.

Ephesians 2:[12] That at that time ye were without Christ, being aliens from the commonwealth of Israel, and strangers from the covenants of promise, having no hope, and without God in the world:

It is simple to remedy this condition. First you must realize and acknowledge you are a sinner before God.
Second you must believe that Jesus Christ came and lived a sinless life and died on a cross for you. You must believe He rose again and is now alive. You must confess your sin to God and ask Him to forgive you based on the finished work of Jesus Christ. You must ask Jesus to come into your heart and receive Him as your Savior and allow God to give you His righteousness.