I am writing this to you, so that you may know that you have Eternal Life: you who believe in the name of the Son of God
Other versions
King James Version
These things have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God.English Standard Version
I write these things to you who believe in the name of the Son of God that you may know that you have eternal life.New International Version
I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.