blow hot and cold

From Aesop's fable The Satyr and the Traveller, in which a satyr declares he cannot trust a man who blows hot (to warm his hands) and cold (to cool his food) with the same breath.

• "For a week, she couldn't get enough of me. The next week, her interest blew hot and cold, and a week later she dumped me."
• "He blows hot and cold. He will speak for or against."
• "Geminis, like air, blow hot and cold. They go this way today and another way tomorrow."
• "The Xinhua commentary said that Chen "blows hot and cold, behaves capriciously and is a hard man to trust.""

• run hot and cold
• suck and blow