it is in my nature to doubt. doubt that she really did mean it,

Did people say things to you in the past that they didn't mean?

doubt that she really would be comfortable doing such a thing if i were to be in the same state of mind again,

Why do you think that she wouldn't be comfortable? Or is it you that wouldn't be comfortable?

doubt that i could ever be brave enough to ask,

You must be used to not asking for your needs to be met. All of us here have or have had this issue. Working past it requires recognizing when we have a need and then pushing ourselves to ask for it.

doubt that she won't get offended and quit me