No amount of cajoling or talking a woman into sex will make her horny.
Let me ask you this: If a big ugly lady came up to you and gave you a long whiney speech about why your dick should be hard for her, your dick wouldn't get hard, would it? Why not? BECAUSE SHE IS NOT APPEALING TO WHAT TURNS YOU ON.
You are trying to talk her into it or to be very good sexually isn't hitting her hot buttons. 99% of good sex is in the mind first. You have to make her feel special, loved, safe, etc. first and foremost. Treating her like the only value you place on her is the frequency of your sex together will have the opposite of your intended effect.