Dear On Time,
Other people’s time is apparently of little if any consequence to your girlfriend. By try everything, I take it you mean bribes, threats, promises, rewards, etc. But have you tried setting acceptable boundaries and limits for you, and then stick to those limits? For instance, limiting the time you are willing to wait to say - 15 minutes before leaving. Arrangements can be made in advance to arrive and leave separately so you can still be on time.
It bears repeating that no one can ever change someone else, only themselves. That’s not to say that transformation and evolution is not possible, or even inevitable. However the expectation that your girlfriend will now suddenly change and be on time because it upsets you is not a reasonable one. She has most likely upset many others for many years with her tardiness, to no avail. Sometimes we love people enough to overlook their flaws. That’s what love does.
Practical solutions include setting her clock ahead and or telling her the arrival time is an hour and half earlier than expected. Or, set limits on how much lateness you are willing to accept, decide what you are going to do about it, then let it go.
The only thing we have control over is our response to outside forces. It is true you have every right to be on time, it is equally as true that your girlfriend has every right to be late (no matter how wrong it is). But you can determine what limits and boundaries you are willing to accept, or not, then act accordingly. Please model self-respect by accepting no less than what you deserve.