Hilchos Lashon Hara chapter 4, section 11

Here is another important rule. If a person wants to get involved with someone else – for example, a shidduch (marriage match), or hiring them for a job – it is allowed to ask about them, even if nothing bad has been heard about them.

Even though people might say bad things about them when asked, it is allowed to ask, because the goal is only to protect oneself, so that later there will be no harm, no fighting, and no chillul Hashem (desecration of Hashem's name).

But the one asking must tell the person being asked that they are asking for a real purpose. This way they will not cause them to sin with lashon hara. Then, even if the other person says something bad, it is for a purpose and is not lashon hara. But one must be very careful, when telling something for a purpose, not to exaggerate the bad things.

If the one asking does not say they are asking for a purpose, it seems clear that they break "Do not place a stumbling block before the blind." The person answering would be saying bad things as lashon hara, even though in truth the information was for a purpose.