'Sincerely' in the Bible

Then Peter, turning around, saw a disciple following. This was the disciple whom Jesus sincerely loved, the one who had also leaned on Jesus' breast at the supper and asked, "Lord, who is going to betray You?"

So have I become your enemy by telling you the truth?

May grace be with all who sincerely love the Lord Jesus, the Messiah!

The one preach Christ of contention, not sincerely, supposing to add affliction to my bonds:

the others proclaim Christ out of rivalry, not sincerely, seeking to cause me anxiety in my imprisonment.

for I have no one like-minded, who sincerely for the things concerning you will care,

Now that you have obeyed the truth and have purified your souls to love your brothers sincerely, you must love one another intensely and with a pure heart.