Earlier quoted context omitted.
This doesn't work. I have tried it. She (my GF) just argues with me about any purchase I try to make that is around the ballpark of what she is expecting me to pay for a ring. e.g. Her: So you want a new MacBook Pro, but you can't afford a $3000 engagement ring? Me: No, I need a MacBook Pro for work. This has been going on for quite some time now.
tell her you'd rather set the $3k on fire - as in, real fire, with smoke and all - while she watches than buy a diamond ring. be prepared to follow through. oh also don't listen to advice on the internet.
Also, don't do this.