I always work to the rule of if you can't say something nice , don't say anything at all, so if the truth will hurt do not say anything, opt out, in these situations i usually look blankly and reply with "pass, next question please" this usually makes the asker smile and change the subject!

for many years i had to hide the truth to protect others who were not strong enough to accept it, eventually i told this truth and was accused of lying!
the person this truth was about then proceeded to lie about it and was believed!

this has left me with a strong hate of lies and big mistrust of anyone who lies to me. i would rather hear the truth or nothing at all, i respect when people opt out of answering a question i pose as i know their views are different to mine and opting out is shielding me from hurt. people who are too honest are not respecting feelings, so i tend to steer clear of these people, those who lie and i find out i drop like a stone.