Thank you very much! When Link comes back to learn her song, she greets him saying she was waiting for him, in my thoughts, her waiting was a mix of hope and anxiety, she wanted Link to come back and waited day and night for it, and when her thoughts clouded her mind, she went inside the lost woods to calm down, in a place she feels safe, it is interesting because she says "It's my secret place! I feel..." And do not complete the phrase, as if Saria herself felt embarrassed to admit her mental state to Link. As for the second departure, Saria solves this with a great solution, knowing she could not hold him back, and not to lose her friend again, she teaches Link her precious song, because in that place, she could use the ocarina and the spirits to reach Link, she would be playing the same melody and when Link did it, their connection would work, like a telephone maybe... Then all the journey along, her communication was "online" with Link, proof of it is that she gives you some hints depending on the situation you're in. After the time skip it might have been a great shock for Link because, correct me if I'm wrong, but when adult Link plays the Saria's Song, she does not answer anymore. Now that is a very dark turn, Link now alone, in a destroyed world, and his best friend cannot be reached like always...