台Taivo A Taiwan Mandarin dictionary

冰炭不言，冷熱自明

bīngtànbùyán,lěngrèzìmíng

ㄅㄧㄥㄊㄢˋ ㄅㄨˋ ㄧㄢˊ , ㄌㄥˇ ㄖㄜˋ ㄗˋ ㄇㄧㄥˊ

Simplified 冰炭不言，冷热自明

1ice or coals, whether hot or cold goes without saying (idiom); fig. sincerity is not expressed in words

Keep 冰炭不言，冷熱自明 and it comes back until you know it.