Could it be that Samrat will somehow understand thay the room was polished with ghee before it was set on fire? It's obvious that the maids clean the house, and it's possible only for them to carry out such an act. Also Maithili had earlier witnessed Mohini handing out that wedding dress to that maid Devyani.
We know Maithili knows Paro better than anyone else and she would eventually be on her side only, that she most probably will not believe that Paro could ever do such an inhumane thing to Dilsher. Could it be that when everyone starts blaming Paro, she and Samrat will do some 2 + 2 = 4 and bring out the truth in front of the family and clear the MU? Now that'd be interesting!