@Pyoro Well she can kill them all, is not that she is getting cocky, the hard part is killing them all while defending Hiro.
@Kettch being in love makes people act stupid, is a pretty big part of being in love, it allows people to ignore blatant faults so that the relationship can progress to a point were the couple is comfortable enough with each other and work those flaws out without the relationship ending, of course that last part doesn't always works out and you end with the classic "i can't believe you are like this! my mother was right about you all along!" fight, well the thing is everyone saw it except the person in love, because love is not blind, love is blinding, and what is being blind is the judgement of a person, usually towards judging their lover, but also towards other things into their life, that can be seen when people in love become less attentive to their surroundings or actions, because they are drunk on feelings of elation.
And a person with a skewered judgement, is well not all that different from a stupid person.
With all that said i don't think Azumi has the stupid that comes from a person in love, she just has the stupid of a person who has been put in a dire situation, which is bad writing since she is a ninja trained specifically to deal with these kind of situations.