His heart seemed to break in two as he watched him walk to the ship with Gandalf. Frodo was leaving Middle-earth with the Elves and like them, he would not return. All those months journeying to rid the world of the Ring had come to this, four years later.
However, though Sam felt his heart was breaking, at the same time he felt glad that his master seemed to finally be at peace. The lines of pain and worry that the quest and the subsequent years had etched onto the Hobbit's face smoothed away as he stepped onboard the ship. Through his tears, Sam watched as his master turned to his three friends on shore, and smiled. It was a smile that the old Frodo, before the Ring had ever come to him, would have given, and it warmed Sam's heart to see it.
After all this time, his dear Mister Frodo had finally found peace.