Anyone could tell what her deepest wish was.
They saw it in her face when she gazed at the couples dining in the restaurants while she stopped by to pick up her take out. Obviously she was only buying food for one.
Sometimes, when she thought she was alone, the expression on her face was one of loneliness. She'd developed too much of a reputation as a bone crusher for guys to consider her as dating material. The fact that she also was fast on her way to becoming an elite kunoichi made most of the boys treat her like she was a bit of a legend, and obviously someone who wasn't their type .
The look in her eyes was there when Naruto proposed to Ino one night at the bar. She was surprised, even more so when her best friend said yes. It was something she wanted more than anything, a man to call her own, someone to treat her like she was the most special thing in the world.
Ino's advice was to go and get drunk, before jumping whoever happened to help her home. Turns out Sakura's a pretty maudlin drunk, her inner anguish even more apparent to the outside observer after a few cups of Sake.
He saw her there of course, wearing that sad face. No one should ever have to feel that way. He knew what it was like, and someone like Sakura didn't deserve to feel that they were alone in the world. Thinking back on certain things, he supposed that he'd been rather derelict in his duty towards her. Though from his point of view he'd been the one to teach her how to grow enough of a backbone to go and request the hokage to become her next sensei. Kakashi really did care, though his methods of helping were subtle and roundabout at best. Occasionally flawed.
Sliding onto the stool next to her at the bar was just his way. His nindo as one could say. Sakura was someone who obviously needed his help, and he'd do his best to see if he could erase that look from her eyes, whatever it took to do it.