If you always say what people want to hear, eventually you forget what you actually think.

Agreeing is a skill and it has a cost that is easy to miss. If every answer is shaped to fit the person in front of you, you stop consulting yourself first, and after a while there is nothing to consult. People call this not knowing what they think, when really the checking has gone unused for years.

Start small and low stakes, since big honesty is hard to begin with. Give one real opinion a day about something that does not matter, like the food or which way to go. The point is reopening the channel, and once it is open the larger things get sayable.