"That e'er was heard or read of. Swear his thought over
By each particular star."
This, if correct, would seem to mean exorcise his thought, try to banish it.
"Profess'd love to him, why his revenges must
In that be made more bitter. Fear o'ershades me.
Good expedition be my friend, and comfort
The gracious queen."
How could his expedition or haste to depart comfort the queen? It would seem to have the contrary effect, as tending to prove her guilt. For 'and' in the third line we might, with Singer, read God, or, as I have done, with Hanmer, Heaven. The insertion of love in the first line seems necessary.