不温不火便不嗳忽冷忽热谁敢嗳
[bù wēn bù huŏ biàn bù ài hū lĕng hū rè shéi găn ài]
Neither lukewarm nor passionate—so no warm feelings; inconsistent and unpredictable—no one can handle this kind of affection easily, showing a fluctuating nature of emotions or behavior.