Meaning of Villainous dictum

“…no adventure too perilous for him to undertake if consistent with the character of a civilian who was at heart a soldier, and who in good faith and without too much qualification assented to at least a part of the frankly villainous dictum that all is fair in love and war.”

What does the sentence mean? I looked up all the words I wasn’t familiar with but still unable to understand the sentence.


He was not afraid to try anything that a brave and noble person who believes that ‘all’s fair in love and war’ would do.

I have two questions:
What does “qualification” here mean?

Is “all is fair in love and war” the villainous dictum or is it a part of it?

“All is fair in love and war” is the villainous dictum.

Qualification = a statement that limits or restricts some claim. ‘Assented unreservedly…to the dictum’.