Two patterns: (1) 问心无愧 'ask one's heart, feel no shame' - a fixed phrase about clear conscience. (2) 无愧于X 'to be worthy of X' - used with titles, ancestors, the times. Negation 无 here is literary for 没有.
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Builds on the Confucian framing in 《孟子》 - 仰不愧于天，俯不怍于人 ('Looking up, ashamed before no heaven; looking down, ashamed before no man'). The same moral standard of self-examination.
