"I know which of the two girls you like better."
Translation:So quale delle due ragazze ti piace di più.
I tried 'meglio' in place of 'di piu', but it was not accepted. Can someone explain why not?
To answer my own question, I'm supposing that Italian only uses better as a quality of an object - ie, one thing is better than another - and not in reference to a degree of liking, as here. In this case, the more correct English translation is "... you like more".
I'm waiting for an answer to this, assuming that your own answer, which you sound a little doubtful about ( :) ) is wrong.
What is wrong with my answer: Lo so quale delle due ragazze ti piace di più ? I have heard it in italian songs: ...Lo so non mi credi, non hai fiduccia in me. Of course pop songs are not an authority, but is it wrong ?
the structure of the second sentence is different, it consists of two parts: "I know (it), you don't believe me". The first sentence is just one part, so there is no 'Lo' to refer to.