Abstract: Sleep assistant system and method for assisting in easing hardship of falling asleep are provided. The method includes the following. Data indicating at least one biosignal is received. A falling-asleep hardship index is determined based on the received data to indicate hardship of falling asleep for a user. Sleep guidance in visual form and/or audio form is provided, based on the falling-asleep hardship index, to assist the user before falling asleep in changing the falling-asleep hardship index for the user from a first state to a second state, wherein the sleep guidance is a portion of user interaction between the second user device and the user. The second state, different from the first state, indicates a less hardship for falling asleep in terms of the at least one biosignal from the user.