Essentials of the Asatru Tradition

II & III. The Nine Noble Virtues - Truth and Fidelity

These two virtues are extremely similar, so I'm putting them under the same chapter

The Havamal counsels that One should speak truth at all times. That is, unless lied to by someone else. it is said by the Havamal that if you are lied to by another, it perfectly acceptable to lie in return, that is, treat lies with lies. Truth is the underlying principle that drives our courage farther. as is stated in the Havamal:

counsel you second; swear no oath
but what you mean to abide by:
A halter awaits the word-breaker
villainous is the wolf-of-vows.

While Truth is never telling a lie, Fidelity is to keep your oaths in what you say you'll do (which is basically truthfulness in a different sense). Fidelity is also being loyal. So things like commitment to your family, your faith, your country, etc.

The Havamal essentially expresses that:

If you find a friend you fully trust 
And wish for his good-will, 
exchange thoughts, 
exchange gifts, 
Go often to his house