How do I get rid of Sasha with light side points?

After learning her language, go to Dantooine. An alien is looking for her in the lobby place (where you land).

You can do it.

She will eventually leave your ship on her own. When she does Zallbar (spelling) will talk to you as you enter the Ebon Hawk.

Well, after finding her in your ship learn her language, sometimes you may have to go over a word like her meaning for 'home' or 'hit' so it may take a while.
Then fly to Dantooine and talk to a green twi'lek in the space port ( the one not wearing a jedi master robe ) and say you are willing to help him find the girl.
Then say that there is a girl by the name of Sascha who speaks a spatter of mandalorian hiding out in your ship and he can see her if he wants.
He tries to speak to her but she can't understand him so you automatically step in and you can speak to her in her language which makes her willingly and happily leave with the twi'lek giving you light side points.

When you've learned her language, go back to dantooine. There will be a male Twi'lek named (I think) lurka ot salem. Talk to him and let him go onto the Ebon Hawk, then he will take her home. Or, if you're lazy, she'll leave by herself right before you get sucked onto the Leviathan.