"Nothing is going to prevent her."
Translation:Inget kommer att hindra henne.
The way that is often taught is that ska implies certainty, and that kommer att implies uncertainty. Note the difference between implying and requiring here. You don't have to guarantee anything, just making or implying some sort of promise or certainty is enough.
As a general rule of thumb, this is an okay method for teaching Swedish as a second language, as it is often correct. But it's also very clearly not how natives exclusively use the words. For instance, in the sentence "nothing will be able to stop her", there's a defined guarantee/promise - yet I'm willing to wager that if you asked a hundred Swedes to translate it, you would get a hundred kommer att and zero ska.
In truth, I do not know what rules govern how we use kommer att and ska more exactly. And I apologise for making it more confusing.
You're absolutely right in that inget ska hindra henne would be a bad translation, by the way. But I don't know why, and the certainty thing is not the reason. :)
I learned from my Swedish teacher that “ska” is used if it's something the subject has planned. And “kommer att” is used if it's something the subject doesn't have power over. So it would even work with this example, since “ingenting“ has no power to prevent “her”, thus you use “kommer att”. :) For this reason “kommer att” is also used if you're talking about zhe weather tomorrow. On the other hand, I was already faced with some sentences where this rule is also not perfectly applicable on. ^^