be at pains to do something

be at pains

To put forth effort toward some goal or end. Annabelle is at pains to make sure her relatives are comfortable when they come to visit. So far, she's cleaned the whole house and set up all the guest rooms.
See also: pain

be at (great) pains to do something

put a lot of effort into doing something correctly: The manager was at great pains to point out that no one would lose their job after reorganization.She was at pains to make us feel welcome in her home.
See also: pain, something