Can you know that you have salvation?
I believe you can, even though many people have told me otherwise over the years, some saying you just will not know for sure until you get there.

Yesterday a young man approached me after church and said he was not sure if he had experienced salvation.
I gave him some scripture – These things I have written to you who believe in the name of the Son of God, that you may know that you have eternal life, and that you may continue to believe in the name of the Son of God. 1 John 5:13

God gave you the things from John (and the Bible as a whole) so that you may know you have salvation.
The greatest tragedy is not from those that question whether they are saved but it is from those that have listened to the adversary and believe they are saved and they are not. These believe in some form of salvation not supported by scripture.

The young man knew he was a sinner. He knew salvation was beyond anything he could do and he gave his heart to Jesus, trusting in Him for salvation.
How will the rest of us know he is saved?
His life will now reflect what he believes and the enemy will do his best to deter him.

To this end I give the marvelous words of Paul – be strong in the Lord and in the power of His might. Put on the whole armor of God, that you may be able to stand against the wiles of the devil. For we do not wrestle against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places. Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand.
Stand therefore, having girded your waist with truth, having put on the breastplate of righteousness, and having shod your feet with the preparation of the gospel of peace; above all, taking the shield of faith with which you will be able to quench all the fiery darts of the wicked one. And take the helmet of salvation, and the sword of the Spirit, which is the word of God; Eph 6:10-17