waiting her beside > [was] attending on her, keeping watch beside her
3 Whom seeing such, for dread he dared not show
seeing such > [seeing; seeing the lion for what he was]
4 Himself too nigh at hand, but turned wide
wide > aside
5 To a hill; from whence when she him spied, 6 By his like seeming shield, her knight by name
like seeming > similar her knight by name > [her own knight; by name = particular]
7 She weened it was, and towards him gan ride:
weened > supposed, imagined gan > did
8 Approaching nigh, she wist it was the same,