[Susan]

Hi Zach, my female boxer that I rescued years ago had no confidence & was nervous, well thats what the RSPCA said when we adopted her, one condition of her adoption was she had to go to doggy classes to build up her confidence with other dogs, but you have already tried that.. if you have the money, I’d look for a dog trainer that deals with fear agrression in dogs, if its a big problem….
also we have coloured coded collars & leads here in Australia that will say, green says “friendly” white says “Deaf” or “Blind” bright Pink say “Caution” blue say “Training” red says “do not approach” orange says “No Dogs” yellow says “nervous” also a yellow ribbon means stay away, if someone has a yellow ribbon on their dogs collar or fence & gate means stay away… just google “colour coded collars” this way people will see she has a nervous problem & keep their dogs away making her feel safe…
Even thought my boxer went to classes, she still did not like other dogs especially if they were bigger then her & would fear bite them, especially if they smelt her bum….your girl might always be like this, no matter what you try, thats just her & its just something from her past, maybe it was bad socializing or something else happened to her, she may always be very timid & scared…poor thing..