I don’t really ‘see’ a beauty / ugly dichotomy, so I’d have a tough time with this question. I think I’d start by trying to get a sense for what they mean by ‘ugly’. If they just wanted to know whether I was attracted to them, I’d just tell them the truth.
If they were looking for a more abstract, ‘on high’ judgment about their worth as a person as seen through the genes they were born with, I’d just tell them I don’t really understand the question. Then I’d segue into a deeper discussion about the nature of beauty. There are different kinds of beauty and something can be beautiful and ugly at the same time.
I hate it when people derive their self-worth from their appearance so I’d try to steer the discussion there if I can.
Is this dude ugly? Maybe, but his features are super interesting, you know, being a Neanderthal and all. What he is is dignified, which is way cooler than actually being beautiful. Anybody can be dignified, it radiates from within.