Chofetz Chaim Daily 28 Elul. Conclusion. If you think the in-laws aren’t going to support the amount promised, you can tell if a) you are positive b) it is a ‘make it or break it’ issue for the boy 3)the boy is really all he’s made to be. If they already made the t’naim, you may say only if you know they will act Al Pi Din, and not just break it off.
Chofetz Chaim Daily 29 Elul If your information is not first hand, you can say it IF 1)the listeners know that, & will make more serious inquiries 2)they won’t break it off because of you. The Chofetz Chaim concludes his sefer by saying that the main idea is to think before you speak!!