He ruled his senses, nor betrayed The grief that on his bosom weighed, And thus his mother’s mansion sought To tell the mournful news he brought. Nor could the gay-clad people there Who flocked round Ráma true and fair, One sign of altered fortune trace Upon the splendid hero’s face.

In plain words: Rama controls himself and hides the grief inside him as he goes to his mother's house to tell her the sad news. The cheerful people around him cannot see any sign on his face that his fortune has changed.