Well she certainly seems/acts like a criminal. I mean, Kematu even gives you the option to talk it out, when he thinks he can kill you right then and there. The Alikiri guys seem like good people, when they interrupt a Redguard woman on the outskirts of a town they dont get harsh/violent but merely annoying. Their story is much more valid than "they are assassins and want to kill me", if they really were assassins why would they be asking permission to enter the town in the first place
Or maybe they are just a band of mercs and not skilled assassins, thus they can't sneak into the town and the one who tries even gets captured and, astonishingly, is left to rot in there by the others who even told him basically "you snooze, you lose". Quite the fellowship right there.
No, I doubt they are are assassins, but I do believe they are just a band of cutthroats, whether or not they work for bad guys as well as good guys doesn't make them good people.
Also, in the cave, they just saw you slicing through a score of bandits. Maybe it would be a good idea to avoid fighting you, if possible ? Hell, even offer some gold and some sweet lies. Quite interesting that he paralyzes her before she can speak.
It may be bad to be fooled by a pretty face, but it's equally bad to be fooled by a sweet tongue.