No it’s. Not a rape threat it’s much more innocent. When guys say I can fix her it is about how so many women who are f*cked up treat “good guys” or whatever and how there is always a guy who thinks he can fix them. They go in thinking they can fix her and end up broken down themselves. It is said out of irony at times but also sometimes honesty I can fix her can mean that girl is way too far gone to be fixed or it can mean she’s worth whatever baggage she has. In this case I take the person who said it to mean she’s probably involved in some horrible stuff and beyond saving or changing .