Trust?

Hypathetically if I cheated on my boyfriend (this didn't actually happen)...
How would I get them to gain their trust back for me for the second time? What qualities could I change in myself in order to be more trustworthy? Do you think trust just comes...

over time, if not what kind of effort do I have to put it? & how should I do it?

It seems like a pretty simple question & I know the basics but I was wondering if anyone could help me a little more specifically

I cheated on my boyfriend.
we had been dating probably nine monthes then.
he completely trusted me then, and cant now.
I told him it was the worst mistake of my life, and how I'd never do it again.
but, he still cant trust me, and it's been 2 monthes-I dont blame him at all.
if it was me, I wouldnt have taken him back.

I think trust comes over time AND has to be earned.

Heh, you cheated on your boyfriend. It's sort of obvious.

no I didn't, my ex just doesn't trust me anymore because he assumed I was really flirty with guys because I tried to make him jealous all the time which was a bad mistake