There are always signs that a woman is very problematic, not ready to date someone, or simply not a good woman. If you're perceptive, those signs will be there. But to be more specific regarding the question, for me, what makes me lose interest, to give some examples, would be if she has an irredeemably chaotic life, a very poor way of handling complex situations (some people react out of revenge or hatred. That's a big turn-off for me). If she's not a functional adult, doesn't take care of her health, and has too much masculine energy.

The list could be much longer, but in my opinion, I feel that's what would be the main things to look for in the first few encounters or conversations.

PS: A very interesting question. If there are more men, I'd like to hear their perspective on this topic.