The Defence of Guenevere Sin Quotes

How we cite our quotes: (Line)

Quote #4

'When you can see my face with no lie there
For ever? [...]' (lines 240-241)

Guenevere uses her own beauty as proof that she has not sinned, or "lie[d]."  Yet again, she avoids using the "s" word and instead talks about lying. Is she implying that lying is a greater sin than adultery? Or is Guenevere maybe trying to divert the jurors' attention away from the issue of adultery by focusing on the lying?