As nouns the difference between commitment and ambition
is that
commitment is the act or an instance of committing, putting in charge, keeping, or trust, especially while
ambition is eager or inordinate desire for some object that confers distinction, as preferment, honor, superiority, political power, or literary fame; desire to distinguish one's self from other people.
As a verb ambition is
to seek after ambitiously or eagerly; to covet.