the.com/repent
Regret with a U-turn attached, because feeling bad is just the down payment.
means To sincerely regret a wrong and resolve to change course because of it.
from From Latin paenitere, to cause regret, via Old French repentir; the re- doubles down on the sorrow, the rest is the soul wincing.
Not just sorryImplies turning around, not merely feeling lousy.
Greek echoBible's metanoia means a literal change of mind.
Slithering cousinUnrelated to reptile, despite both making you crawl.