Commentary for Arakhin 31:48

As to there being found a heter [a halachic permit] in the words of Chazal to speak it before three, this applies to something which is not an absolute taint and which can be understood in two ways. It is well known that such things depend on how they are said. It is such a thing that Chazal permitted to say in the presence of three, the rationale being that since he says it before three, he knows for a certainty that these things will come to his [the object's] ears (for "your friend has a friend, etc."). The speaker, therefore, heeds himself in speaking, that what he says will not be understood negatively. (Let one illustration serve for all cases of the same kind. If one is asked: "Where is fire found?" and he answers: "You can find it there, where they always cook flesh and fish." This can be understood according to how it is said at the time. If he wishes he can say it in such a tone that contains no taint against his friend. For in truth, there is sometimes no fault in this. It may be that he has a large family and that the Holy One Blessed be He has blessed him with wealth, or that he is an innkeeper or the like, and that when he [the speaker] is asked where fire is to be found, he answers [quite appropriately] that there is no fire to be found now except in that house, where they always cook, etc. All of these things in the category of the "dust" of lashon hara depend upon how they are expressed at the time. But if the "tone" of his voice and movements is that he [the proprietor of the house or the inn] overindulges in feasting, even though this is not an absolute taint, Chazal has termed it the "dust" of lashon hara, and it is forbidden to say it even in the presence of three.)