[NorthMountain]

If you are seated in an exit row, the FA will ask you to verbally, out loud, affirm that you have read the instructions on how to operate the exit, that you understand the instructions, that you are both willing and physically able to carry them out, and that you are willing to assist other passengers. You may be asked more than once.

It's fairly simple, and a simple "Yes" is sufficient answer. If you answer "No" the FA will have no trouble finding someone willing to trade seats with you.

[Kipp]

It probably didn’t help that the woman said that she wasn’t going to help anyone get off the plane, that she was going to save herself.

[Blueflag]

Also you can’t sit there if you require or request a seatbelt extension. IIRC

[Brian Griffin]

“If you are seated in an exit row”

The airline assigns seats unless I choose to pay extra.

At the time of booking, the airline could ask if I was willing and able to help with exit row responsibilities if it doesn’t have a person already assigned.

I only learned of exit row responsibility eight days ago.