Am I worth a chance?

I've got to know her four years ago and just had to let her wait because I had to finish college first. Then I wanted to find a job to be able to afford being in a happy relationship. But things changed as soon as I graduated when she suddenly became colder towards me and started to date other guys.

A friend of mine commented that she might not feel as needed anymore as she did while I was just down and exhausted, clinging to her helping hand. Yet I never said I'd just drop her and go new ways, It was just about the job issues. Now that I have a job for about 1 1/2 years now, she meanwhile ruined two relationships, as quickly as she did before, according to what her cousin told me.

I can't say I'd be a better partner since I hadn't had much relationship experience so far. Anyways on the one hand I could go ahead and go with dating women around me who I'm closer to right now. On the other hand I don't know them as long as I know the other woman now. I've gone through the same stuff as her with short relationships. But she seemed to meanwhile withdraw and become fed up with failing with relationships. I have let her know that I was interested in going out with her. Twice now she told me I was just an acquaintance to her, yet that was while she considered herself happily taken. Altough she treated me like before when she had quit with the first guy she told me of. She even told me when she quit with him at the time when her friend told me she had a new guy now. Which she meanwhile quit with as well.

It all sounds quite sad I guess. And without sounding mean, my job was more constant than her relationships. But my trouble had been college before hers had been relationships. I know how stressful such things can be. But how do you think could I get her to understand that I'd not be just someone like the past two guys just walking in and out of her life?