This answer is based on your email response asking you to clarify your question. You responded, "How does the character of Francis Macomber change from beginning to end?"
In the beginning of the story, we discover that Macomber has a lot of guilt about running away from an encounter with a lion. His male pride is wounded and the wound is kept open by his wife, Margot, who often brings up the incident sarcastically. She makes it clear that she does not respect Francis.
Wilson, Francis's hunting partner on this safari, does not respect Francis either; so much so that Wilson and Margot have a fling right under Francis's nose. Neither one seems to care much when Francis finds out about the infidelity.
Incensed by their disrespect, Francis is infused with a new drive. He and Wilson go after some buffalo. In a series of what may or may not have been mistakes, Margot shoots Francis in the head. Thus, the ironic title, "The Short Happy Life...". Francis brief stint in the macho spotlight is short-lived.