dressed > dressed; arrayed (with armour, etc.)

2 For every shape on him he could endue:

endue > put on (as a garment)

3 Then like a king he was to her expressed,

expressed > portrayed

4 And offered kingdoms to her in view,

in view > in her view; or, lacking the final comma: with the object, hence: to prevail upon her

5 To be his leman and his lady true:

leman > lover, mistress

6 But when all this he nothing saw prevail,