find out the hard way

find out the hard way (third-person singular simple present finds out the hard way, present participle finding out the hard way, simple past and past participle found out the hard way)

1. To acquire knowledge through failure or any other undesirable experience.

   I don't know how well seatbelts protect you, but I certainly don't want to find out the hard way, so I use them either way.

   You can't assume that someone else will call an ambulance. I learnt that the hard way after crashing my bike.

• learn the hard way