I really really wanted to believe her. I did. But something in my gut felt wrong after speaking to Kematu. I think she was chased out of Hammerfell for the reasons he said, because why would she need to feel afraid in a place that had completely freed itself from Thalmor? Wouldn't she be safer there than fleeing to Skyrim where Elenwen's patrols move freely and do as they please? And if she pissed of the Thalmor, then why aren't the Thalmor after her? They don't need Reguards to do their dirty work in Skyrim. They sure wasted no time coming after the Dragonborn when she/he was searching for Esbern.
On the other hand, if you want to make an argument for helping her: one of their guys is in prison, they are hiding out in a den of thieves and they are harassing every Redguard woman they meet. The Jarls of Skyrim have every right not to tolerate that bullplops.
Still, almost every crooked person in Skyrim has tried to off me after doing their dirty work: Mercer,Jaree-Ra,Astrid,Ancano,Chief Yamarz....Kematu didn't. He paid me and went along his merry way. And if Saadia did what they claim she did, then she needs to be brought to justice. I cannot fault the Alikir for that. A person commits treason of that magnitude, they can expect to pay. Pretty or not.
It's really up to your moral code and your perceptions, but my opinion in that Saadia's pulling your chain.