Pre-wedding is a time where people get all antsy and start looking at their future spouse in a more discerning way. Small things might be seen as signs of bigger things and "never change" flaws that are easy to overlook.

Anyways, it these situations, you gotta follow the protocol. It's easy to come up with something non-offensive but truthful in its essence. You can have emotions ranging from neutral to slightly positive (relief), but it's important to recognize how saying those out loud influences the person asking.

Let's say I think someone has the holy trinity of stupidity, self-centeredness, and outspokenness, but also is a family man. You can express empathy for the suffering of children (doesn't cost a dime), while leaving out the part where your morning coffee after hearing the news tasted especially delicious.