Eye contact rules change between cultures. Looking down can mean respect, not shyness.

What you read as confidence or evasion is a local habit, not a universal one. In plenty of places, holding an older person’s gaze is rude and lowering your eyes is polite, so someone doing it correctly can look shifty to a person raised on the opposite rule. Reading character off body language only works inside the culture that taught you the code.

When somebody’s manner strikes you as off, hold the judgement and listen to what they are actually saying. If you work or study with people from elsewhere, ask rather than guess. Notice too that your own habits are being read by someone using a different key.