Is there really a universal foolproof way to be "appropriate and
sincere"? So what's the favourite colour of all women on this
planet? Or the favourite food of all women? 
Look, you just need to do what you deem fit as ultimately, it's you
who will have to live with the consequences of your own actions -
if you're going to fail, at least fail knowing that's a method you
believe to have been the best(you don't get a second shot at
everything in life, mind!).
Just be yourself - acting "confident" may fool her for the instant,
but it certainly isn't going to work in the long term. So why not
show the true you and let her decide if she accepts you for what
you're? 
