sell > saddle single > {Solitary; unsupported by a sword}
4 But wanted sword to wreak his enmity.
wanted > lacked [a]
5 "He is a great adventurer," said he, 6 "That has his sword through hard assay forgone,
assay > trial; endeavour; assault forgone > forgone; forsaken (cf. Braggadocchio's own account at 203.17)
7 And now has vowed, till he avenged be 8 Of that despite, never to wear none;
despite > outrage none > (The double negative serves as an intensive)
9 That spear is him enough to do a thousand groan."
him enough > [enough for him] do > cause, produce groan > [groans]
203.13