In two consecutive experimental studies we evaluate the influence of robot’s smiles on user’s trust to the facts, reported by the robot. In each experiment, two F-2 robots reported “hard to believe” facts and the user had to indicate, if he trusts the received information. In the first experiment (N = 54) one robot smiled after the utterance, while the other robot did not. Robot’s smile increased subjects’ reaction time, but did not affect the level of trust. In the second experiment (N = 24), smiling behavior was updated: robot was rotating its head, skewing its gaze direction to the user and rising its eyebrows. People loved this robot and preferred it to the other, non-smiling robot. At the same time, the level of user’s trust to this robot dropped: people noted its smile and reduced their level of confidence to the reported facts.