In terms of construction of a thesis statement about truth, more information would be needed. Seeing that Blanche is included in the tags, perhaps there might be something to be said about Blanche's inability to be truthful with herself. There is much in way of self- delusion within Blanche. Part of this might be due to the fact that much of her true reality is too difficult to endure. Blanche's "truth" is a form of denial, to deny that which is painful and hurtful. I think that this might be one direction in which to go. The other direction about "truth" and Williams' work might be in the larger sense. The notion of "truth" in the play is defined by power. For example, Stanley uses his power to convince Stella that Blanche is insane. Blanche used to feel power in her own world, and at that point, truth could be more readily embraced. In the end, those in the position of power are able to define what "truth" is, making it a concept that is contingent on power and who possesses it. This helps to bring out the fact that Blanche has a tough time understanding the world and how it operates because truth, something that should be universal, has become victim to contingency, similar to Blanche herself.