Try speaking slower, don't use slang enunciate etc. I have a lot of international fam, you have to speak clearly and slowly so they can understand , I got a lazy tongue and I'm prone to muttering so it can be tough but it's worth it. As far as understanding her id suggest Yu just keep talking to her, don't let the language barrier dissuade you once you start to get know her you'll be Able to fill in the blanks. Also chatting via messengers can be helpful.
