'Sincere' in the Bible

I will praise You with a sincere heartwhen I learn Your righteous judgments.

by purity, by knowledge,by patience, by kindness,by the Holy Spirit, by sincere love,

Now the goal of our instruction is love that comes from a pure heart, a good conscience, and a sincere faith.

clearly recalling your sincere faith that first lived in your grandmother Lois, then in your mother Eunice, and that I am convinced is in you also.

By obedience to the truth, having purified yourselves for sincere love of the brothers, love one another earnestly from a pure heart,