There is NO GUARANTEE of SALVATION

Jesus Christ never gave any guarantee of salvation. He said that He will never leave us and He will never forsake us but if we wish to follow Him we must deny ourselves every day, pick up our cross and follow Him. We have to go after Him and follow Him until the very end. He said that those who endure until the end will be saved.
Jesus also warned that the gate is straight and the door as narrow that leads to eternal life and FEW will find it. Therefor He said:”Strive hard, to find the narrow door because many will try hard and not be able.” Jesus said that if we deny Him He will certainly deny us also. Jesus Christ is faithful but if we are unfaithful to Him then He will reject us. We have to GO AFTER HIM, stay with Him, serve Him every day until the very end of our lives or else we will not have eternal life.
There is no guarantee of salvation. Only those who endure with Jesus Christ, who obey Him, who follow Him  and who stay with Him every day of their lives until the end of their life, only they will have eternal life.
May Jesus bless you.