"Gonzalo's guilt valorizes his conduct and speech" (Yachinin 43).
Gonzalo is a old and honest lord. But he constantly plagued with guilt. Why? I'm not too sure. It might be because he helped Prospero and Miranda escape to the island after Prospero was usurped, and now Prospero is getting revenge on all those who wronged him. I was not able to understand why he felt so much guilt through his speech - it seemed like all he did was remark on the beauty of the island.
In Act 5, Scene 1, Ariel remarks that all Gonzalo does is cry. I truly have no clue as to why he constantly cries. Is all of this his fault? The ambiguity within the play leave this question up for grabs constantly.