When we speak truth to believers or non, multiple tests apply for doing so correctly:
1. Be accurate. 2 Tim 3:16-4:2
2. Be gentle. Gal 6:1
3. Be loving. 1 Cor 13:1
4. Be kind. Rom 2:4
5. Be wise. Jms 3:17
If you can't be all at the same time then...
6. Be quiet! Prov 17:27-28 - James Grote