Allegation: I had sex with Y while she was intoxicated

I asked her why she didn’t reply when I asked her, and she told me that she had. However, I had asked her several times, and I heard nothing.

Seems a better way would be to ask in a way that requires a positive response. Something along the lines of "do you want to continue".

Then a missing response, regardless of reason, is naturally interpreted in the safe direction.

This would be similar to how STOP buttons on machinery should be normally-closed, so that a broken wire is interpreted as if the STOP button was pressed.