What's true??

Here are few lines from one of my favorite song:

Nainon ki mat maaniyo re
Nainon ki mat suniyo
Nainon ki mat suniyo re
Naina thag lenge thag lenge naina thag lenge

This song with beautiful lyrics and lovely music makes me think what one should trust. Probably one would call it to go by heart but Is it acceptable to ignore what eyes are expressing?

In contrary, I read somewhere:

"Those true eyes Too pure and too honest in aught to disguise The sweet soul shining through them"

What is true and what is fake, what is ethical and what is unethical, what one should follow - mind or heart. I find these questions the toughest ones when it comes to believe someone whom I don't know much.
Sometimes, I rethink my decision just because the other thought occupies mind at last moment.

I wonder....If it is hard to trust the most beautiful creation of God, Eyes, what one can bank upon?