People are forever telling each other to 'face facts'. If they expand this simple suggestion, their longer, more philosophical explanations tend to center on the idea that we do ourselves no favours when we are unwilling to recognize a reality - because people who fool themselves, tend to make foolish choices. Perhaps they do. But are these choices any more foolish than the ones made by the folk who have fooled themselves into thinking that they are not fooling themselves?
It is important to tell the truth. You do not, though, have to reveal it in graphic detail. Blow-by-blow accounts are not needed. As long as you give the right general impression, you can withhold a lot of difficult information. Say as much as you truly need to say. Think about how it will be heard. Be delicate, discreet and diplomatic but don't succumb to the temptation to be misleading. If your own conscience isn't completely clear how can you decide something?