I’m sure you will get plenty of very sincere responses, but do you really expect any human to actually know if someone is saved or not?
Colosians 2:2 and other places indicate that you can. That the Holy Spirit can give that Assurance "the wealth that comes from the full assurance of understanding".
Also Jesus Said in the Gospel of John "Truly Truly, I say to you, He who believes Has Eternal Life" - John 6:47 For one must Understand that Faith (belief) is the Gift of God. Therefore if you have Truly believed in Your Heart that your Sins are upon the Lamb of God, and paid for. Then, according to this verse - you have Eternal Life.
It is time to Believe and Live within that Assurance.