You're going to need to bring more context with this question. But generally if a woman doesn't trust you it's because you're giving her vibes that make her think you're a rapist. Here's a good guide on how to be less creepy.

http://www.wikihow.com/Not-Be-Creepy

A good way to build trust is to openly share some weaknesses or character flaws. We don't trust people who pretend to be perfect.

Pretty compliment her and then just say something like you are very beautiful then say I don't know why you are with me because of... enter flaw here. I mean not sure this will work 100% of the time but hey it has worked for me.

Yeah playful cockiness is always good, and definitely should be a part of what you do.

But at some point in the first 15 minutes, you also have to make clear that you are 'real', and that you aren't really stuck up. If I were you though I'd try to do it in under 10 minutes. OR if you notice you went too hot too quickly with the cocky stuff, then bring it out earlier than that as a form of recovery from over cooking it.

Cocky and Funny is another descriptor for 'teasing'. Just be careful as thinking about and trying to be cocky can sometimes just make you look like a cock if it isn't calibrated well. And maybe it's just a matter of practice to hit the right notes.

The trouble with you assholes is that you are so busy pretending to be someone that you're not and giving off really shitty vibes that you're a big, fucking fake. That's why girls don't trust you stupid morons. Get a clue.

Just last night a buddy of mine and myself were having some drinks at a very busy bar. This bar is known for bringing out the summer time hotties and new faces all of the time. Before I even showed up, he was already talking to a girl. Nothing special or too impressive, but she was cute to say the least.

Throughout the time I spent with them, she said several things that lead to her not trusting my friend. Remember, they just met. So usually... This is a bad sign.

Girl: "I don't trust a man who can dance"
Buddy (with nothing to lose on this one): "Good thing I can break it down then." (starts dancing)
Girl: "Ok, so it looks like I just can't trust you, huh?"
Buddy: "I wouldn't trust me either. I'm wearing a blue shirt, my hair is spiked up, I have a tan and I can dance. I'm just not trustworthy!"

All with a smile on his face and having fun. By this time, she has invited us out to another bar down the street where her friends work. We share some drinks there, meet up with her friends, but proceed to head back to the bar we came from where it was busier and had more potential. Like I said... She wasn't the first on the bucket list, but she took the bait right from the start. My buddy and myself started turning anything negative she had to say or think, into a joke that was against ourselves. Now that them two have hit it off - I did my usual keeping it friendly and playful. Things like "don't worry, I have a small dick. So even if I did hit on you and got you interested in coming home with me, you wouldn't call me back anyways. You should go with him tonight" and we shared a laugh. Next thing you know, they take off. He texts me in the morning letting me know that he successfully got laid last night.

My point here: There's benefits to acknowledging your potential flaws, and laughing about them. Letting them laugh too and turning it around to be something it probably wouldn't have been if they didn't find you funny.