In act 4 scene 3 of macbeth, what forces has malcolm promised?

Answer 1

"Forces" can mean an army or men who fight. The answer's on this page. A modern English "translation" is on the right side:

http://nfs.sparknotes.com/macbeth/page_170.epl

Answer 2

The English

Outside King Edward’s palace, Malcolm speaks with Macduff, telling him that he does not trust him since he has left his family in Scotland and may be secretly working for Macbeth. To determine whether Macduff is trustworthy, Malcolm rambles on about his own vices. He admits that he wonders whether he is fit to be king, since he claims to be lustful, greedy, and violent. At first, Macduff politely disagrees with his future king, but eventually Macduff cannot keep himself from crying out, “O Scotland, Scotland!” (IV.iii.101). Macduff’s loyalty to Scotland leads him to agree that Malcolm is not fit to govern Scotland and perhaps not even to live. In giving voice to his disparagement, Macduff has passed Malcolm’s test of loyalty. Malcolm then retracts the lies he has put forth about his supposed shortcomings and embraces Macduff as an ally. A doctor appears briefly and mentions that a “crew of wretched souls” waits for King Edward so they may be cured (IV.iii.142). When the doctor leaves, Malcolm explains to Macduff that King Edward has a miraculous power to cure disease.
Ross enters. He has just arrived from Scotland, and tells Macduff that his wife and children are well. He urges Malcolm to return to his country, listing the woes that have befallen Scotland since Macbeth took the crown. Malcolm says that he will return with ten thousand soldiers lent him by the English king. Then, breaking down, Ross confesses to Macduff that Macbeth has murdered his wife and children. Macduff is crushed with grief. Malcolm urges him to turn his grief to anger, and Macduff assures him that he will inflict revenge upon Macbeth."

MALCOLM:
Be not offended:
I speak not as in absolute fear of you.
I think our country sinks beneath the yoke;
It weeps, it bleeds; and each new day a gash
Is added to her wounds. I think, withal,
There would be hands uplifted in my right;
And here, from gracious England, have I offer
Of goodly thousands: but, for all this,
When I shall tread upon the tyrant's head,
Or wear it on my sword, yet my poor country
Shall have more vices than it had before;
More suffer, and more sundry ways than ever,
By him that shall succeed.