It doesn't work like that

First, stop trying to ask her out, she's given you her answer. The way that you don't seem to take no for an answer is probably why she will never date you. Second, the fact that you think she won't get over heartbreak, avoid abusive cheaters, and have "something great" ONLY UNLESS she finally caves into your constant advances raises a ton of red flags. You probably mean well for her, but I'm glad she rejected you because I'm sure she agrees you don't seem very good for her either. As for the question you posed, be her friend. Teach her how to recognize abuser tactics, trust her instincts, set clear boundaries with potential boyfriends, how to confront people who violate those boundaries, etc. And STOP trying to get with her while you're doing it. That makes it seem like you're only being nice to her because you want her for yourself, don't be transactional. Be her unconditional friend because you want her safe/happy and nothing more.

This sounds better if you re write it: Today I made unwanted advances towards a girl who has repeatedly shut me down in the past. This girl has been mistreated and abused by others and is now being harassed by me, why can’t she see how great I am? If you were truly that great, she wouldn’t be rejecting you, you have a warped perception of yourself.

Back off, asshole. Move on, nothing to see here. To her, you're nothing but another abuser who wants to force his will over hers.

Stop obsessing over her and go find someone else. You might find someone even better.

She might be able to recognise something great, only you're not it. Why would she go out with a guy who can't take no for an answer and is full of himself?

If you were truly great, you would have tried being a shoulder to cry on... not just a dick to ride on. you sound overly opportunistic and not really like someone who cares about this girl. IF you actually did care about her you would have been the stable guy friend she "needed" (if she needed it at all). TLDR, you are not a great dude, you are a "nice" guy. you are the exact toxicity she doesn't need, and hopefully doesn't fall for...

So you've repeated harassed her by continuing to ask her out when she's clearly not interested. "why can't she just see a good thing". You are the epitome of a red flag.

First thing you learn in an abusive relationship is to avoid people who don't accept a no for an answer so she's doing everything right so far. You're a walking red flag. She dodged a bullet which is great :)

You won't take her no for an answer. once should have been enough. you're not something great. you're just like everyone else. stop trying to force her into anything. the fact she can't see red flags waving in her face but yours are big and neon enough that she can see YOURS is a problem

Give up, she clearly isnt interested in you

... leave her alone, you creep. She has made it clear that she doesn't want a relationship with you. Get that through your head and move the **** on.