In some cases honesty is a somewhat variable commodity, requiring close attention to throttle control. Between us men, honesty is pretty much as direct as it is brutal most of the time. But when men are approached by their significant other, and asked such questions as; "Sweetums, does this dress make me look fat?" Sometimes the best thing that you can do is to ensure a nice big sandwich is close by. Not just any sandwich mind you, but one that is guaranteed to take a while to choke down (in this case VERY big bites are HIGHLY advised). During this time, it's okay to talk with your mouth full in an attempt to explain to her just how much your mother had instilled it upon you during your youth, quite possibly with the use of physical reinforcement, that it was impolite to talk with your mouth full (blowing a chunk or two of sandwich meat on to the counter top is acceptable in this case, as it will help to further emphasize your point).
With any luck, not far into this display the significant other will either become totally disgusted with the copious amounts of airborne sandwich debris, or simply loose interest all together and find another dress to try on. It should be noted that in this instance it would be a good idea to keep the sandwich close at hand just in case it is once again required.