Well i am certainly relieved to hear you are going to work with Roxy and give her a chance, please never consider putting her to sleep as an option, it should never be one for a perfectly healthy animal, i used to own a netherland dwarf rabbit, to be honest she was never the best pet, she could be a bit nippy at times, but we adored her and loved her all the same, if Roxy is great out of the cage, then what is the big problem, so she gets a bit agressive when you approach her cage, that is no big deal really is it? it is probably like Karen suggested YOU are invading her territory, so i suggest you get some books or go online and learn about bunny behaviour and continue to work through this problem with Roxy,good luck.