In the very beginning, Estragon tries to take off his boot, but "He gives up, exhausted,rests, tries again " (page 2).
"Suppose we repented" (page 5).
Repentance is not an option because Estragon and Vladimir laugh it off. So they turn to suicide. Vladimir says to Estragon "You're my only hope" (page 12).
The boy tells Estragon and Vladimir that their waiting for essentially for nothing, as Godot won't even come when he says he will:
BOY:
(in a rush). Mr. Godot told me to tell you he won't come this evening but surely tomorrow.
With their hopes dashed, Estragon suggests putting an end to their pity of an existence by suicide:
ESTRAGON:
(looking at the tree). Pity we haven't got a bit of rope.
VLADIMIR:
Come on. It's cold.
He draws Estragon after him. As before.
ESTRAGON:
Remind me to bring a bit of rope tomorrow.