"Mystics and Showmen" was the example Mathilde brought up when she was talking with Panoramia, but all things considered she might have wanted to make her Wind sound more impressive/admirable to her date. Conwoman doesn't sound as catchy as a mystic or show(wo)man.
I imagine it's also nearly habitual for a grey wizard. One of the big important tasks for the Grey College is making sure there aren't any Ulgu Conman, and that the public doesn't feel at risk of getting screwed by Ulgu conmen.
She might not mention that for the same reason that she doesn't mention becoming a daemon bomb: That only happens when you do it
wrong.
You could say the same of Mathilde.
She has little direct inclination to be an Assassin and her god is not a fan of violence either.
Yet we do have the skills and we occasionally find ourselves in situation where assassinations are the best path forward.
But Ranald
is at least a god of sneakiness. That's 50%, and honestly the rarer half, because all gods are ok with violence when directed against Chaos and such, and there's a bunch of war gods (Sigmar, Ulric, Myrmida,...) while there's not that many gods of sneakiness. (Ranald's opion of violence is also a whole theological debate I don't care to get into right now).
So Mathilde at the very least had an inclination towards sneaking, and from my reading, didn't have a particular
disinclination towards fighting. (When she got out of the college, she soon went looking for trouble in Eagle Castle, resolved it by stabbing. So far it doesn't say much either way, because she was quite sheltered to that point. But her reaction to violence wasn't "Let's not do that again", it's "Let's make sure I don't suck at it next time")
And yes, Mathilde's choice of Ranald isn't the be all end all of her personality. But we know a whole lot more about it than we do about Eike, based on having access to her internal monologue, circumstances and sheer screen time. And it's still a pretty good basis for judging her personality (though she is more pious than most).
So taking Eike's choice as indicating that she doesn't want to fight and kill things seems reasonable, until we get to know her better.