Definitly!! The whole Bible can! The Bible is a book of God's words written by man. It is 100% true and can be trusted no matter what.
It depends on your situation. The reason there can be contradictory verses is that different teachings applies to different situations. So make sure to reflect if your situation reflects where the teachings should be applied.
Yes, the new testament can be trusted. It is a dimension of lifestyle God wants for people. It is God's inspiration to make us live triumphantly