How can I convince my mother that she really does need assisted living?

My mom is going to be 89 in November and for the past 2 years has developed dementia. It is to the point now where she needs to be looked after. She is in good physical health, but her short term memory is pea soup. My sister and I just petitioned the court for guardianship, which was granted, and now we are trying to get her to move to assisted living without a bloody battle. We have tried every method of persuasion, to no avail. She lives alone and thinks that absolutely nothing is wrong with her. She is walking around alone and forgetting to lock her doors, will not allow a Life Alert in the house and a host of other worrisome things. Does anyone have any ideas of how to persuade a tough old bird that this is what she needs?? I understand that most people fight the change in living arrangements, but she is to extreme, flatly refusing to consider it. Should we just pick her up and move her??? Yes, she is in danger, sometimes.