One should not trust a person undeserving of truth, nor should one trust too much a person worthy of trust. The anger from blind confidence is such that it cuts the very roots.
न विश्वसेदविश्वस्ते विश्वस्ते नातिविश्वसेत्॥ विश्वासाद् भयमुत्पन्नमपि मूलानि कृन्तति।