'Sincere' in the Bible

in pureness, in knowledge, in patience, in kindness, in the Holy Spirit, in sincere love,

so that you may approve the things that are excellent; that you may be sincere and without offense to the day of Christ;

but the goal of this command is love, out of a pure heart and a good conscience and sincere faith;

having been reminded of the sincere faith that is in you; which lived first in your grandmother Lois, and your mother Eunice, and, I am persuaded, in you also.

Seeing you have purified your souls in your obedience to the truth through the Spirit in sincere brotherly affection, love one another from the heart fervently:

This is now, beloved, the second letter that I have written to you; and in both of them I stir up your sincere mind by reminding you;