Saria and Link had been together throughout their childhood, and between them they shared a strong bond. Saria, unlike Mido and the other Kokiri, accepted Link despite him not having a fairy companion most of his life. Saria was Link's only true friend, and he confided in her and relied on her support when picked on by the other Kokiri for being different. Being an outcast was difficult for Link, but without Saria by his side it would have feasibly been unbearable. The fortunate consequence of Link's exclusion was the profound friendship that developed between him and Saria.

Presumably, Saria knew that Link would eventually leave the Kokiri Forest (whether this was predicted knowledge based on the fact that he was so different as to not be a Kokiri, or the Great Deku Tree had revealed this truth to her in one of their conversations, it cannot be known). She was unusually prepared when Link's quest forced him out of the Kokiri Woods: Link, not wanting to confront his feelings about leaving, attempted to depart without speaking to Saria; two steps ahead of him, Saria was already waiting for Link at the exit of the Kokiri Forest.

For the first time, Saria appeared solemn: although materially prepared, she wasn't emotionally ready to lose her best friend. However, being a perceptive and understanding individual, she knew attempting to stop Link would be unfair to him. So, to calm her conscience and make sure Link would always remember her, Saria gave him her most treasured possession: her ocarina.

Later, when Link returned to see her, Saria taught him her personal song so they could communicate, even while long distances apart. That way, Saria was able to look after Link and help him in his endeavours, even from afar.

After Link opened the Door of Time and was sealed in the Chamber of Sages, throughout the seven years that then passed Saria believed Link would return. Even after such a long period of time, she still held faith in her friend. When Link was released, he's informed by Rauru that Saria may have been in danger. Immediately Link set off for the Forest Temple.

Link was obviously distressed when, upon arriving at the Sacred Forest Meadow, he found the stump Saria had always sat upon empty. But before Link became discouraged, Sheik appeared with a song that reminded Link of the fond memories he and Saria shared as children. Contacting Saria and hearing her say she always believed he would come back provided extra strength for Link to get through the evil-infested temple.

After awakening as a Sage, Saria admitted that she didn't originally want to become a Sage. Although she doesn't specify why, there seems to be only three possibilities: she felt she wasn't capable enough, she didn't want the responsibility, or she disliked the fact that she'd be separated in yet another way from Link. Considering her closeness to him and the displeasure they both suffered at their first parting, the last option seems the most likely.

Although both genuinely care for each other, a romantic relationship developing between them is not a high probability. The barriers that love would have to cross are quite resolute, and it's unlikely that even they would be able to compensate.

Firstly, as a Sage, Saria's top priority is protecting the Forest Temple and making sure Ganon stays trapped in the Sacred Realm. This keeps her away from everyone, excepting the other Sages.

Secondly, Saria is a Kokiri, fated never to grow older than she appears, while Link will continue to age and mature. This age difference would make it impossible for a relationship to occur.

Lastly, Saria's feelings appear to be unrequited: Link doesn't seem to have any romantic interest in her or anyone else. Even so, Saria is content with being Link's dearest friend, and Link is certainly glad for that friendship.