What Rasha is discussed?
Radak: He relies on his great strength, and does not look to Kel and does not understand.
Why does he have many pains?
Radak: They are due to his many sins. No one can save him from his pains!
Malbim: Many things pain him - illness, hunger and all afflictions. Refer to 32:10:3:4.
Will anyone who trusts in Hashem be surrounded with Chesed?
Shocher Tov: [Yes;] it is even a Rasha.
Eichah Rabasi (4:23): This teaches that if a Rasha repents 1 , Hashem accepts him.
Radak: It is one who understands that he has nothing else to rely on; good and bad come to him according to his deeds. He needs to repent from his sins.
Malbim: Even if he has illness, hunger or all afflictions, they do not pain him; he considers that he is surrounded with Chesed. They guard the wild animal (body) from veering from the path and harming him.
Lev Eliyahu (Shemos p.63 citing Moreh ha'Nevuchim): If one has great Bitachon with Hashem, he has connection and Devekus in Hashem. Without this, it is not Bitachon. If he clings to Hashem, no harm can come to him.
Yefe Anaf (on the Midrash): Many sources explicitly say that Hashem accepts Teshuvah! Rather, the text should say that even if he does not repent, just he trusts in Hashem, Chesed will surround him.