Is it really hard to win over an ex girlfriend when we messed up?

I heard from my good friend my ex girlfriend might come back and is willing to give it another chance, last one though. However, she's taking her time and is still hurt at this moment. I've failed her by being tardy on some of our dates and being late on other things except work, not following through some promises, focusing too much on myself, ignoring some of her needs (she was very verbal in the beginning so I can't really complain there) and doing the action she wanted at the last moment when it was too late.

This was her response 6 months ago when she declined me:

''Well I suppose its better than never but why now? Why at the last minute when I'm about to take the flight? I would've said yes before but not anymore. I'm still not impressed.''

According to my friend, she want to feel secure again that she can rely on me, if I've changed or not, etc. Last week was the 2nd time she declined saying she's not sure. She said to continue working on myself, I can ask again in a year later and then that'll be her final answer. I've been seeking a counselor for some time, been working on myself.

Is it really that hard to win over a woman if we messed up? Win her over hear once again? Make her crazy over me like she was in the beginning?

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1 y
I never cheated on her nor was ever abusive though. But yes still failed her. I want to be a better version for myself overall, for her too. Make myself the man she falls for again, make her say yes to me on the 3rd time, make her want me.
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1 y
It took losing her and seeing how bad my flaws were to realize what I had.
Is it really hard to win over an ex girlfriend when we messed up?
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