I can address her concerns/fear of abandonment, but that takes 10 seconds at most... .It does nothing to satisfy her.
You are not going to satisfy her. You can only be consistent.
In reality, you reassure her "nothing bad is going to happen (no specifics)'. Then nothing bad happens.
If this pattern is constantly repeated you can assure her "nothing bad has happened before and thats not going to change". She will eventually accept this as the reality even if it takes a lot time.
Be reasonable and considerate, know your own reality and dont try to sell it to her. She has to choose to let go of her perception, you cant convince her to that will only create resistance.
I have been through, and passed, this stage. The journey however took a whole lot of drama including self harm and serious destructive behavior on her part in attempt to thwart it. We have no conflict over these issues at all now. Why? because nothing bad ever happened. In fact as a result I was happier and she learned that as a result I was more amenable to other aspects of her neediness because i was getting my "slice of life" as a trade.
In short, be fair, considerate and consistent. It is your life and you have a right to have some say in it. Giving in to neediness just perpetuates it and harmful to both of you in the long run