boxer briefs

comfortable

come off, become detached / subside (especially of a fever, pain, etc.) / to come off / be taken as (be interpreted in a certain way) / to keep, to maintain / the potential form of 取る, to be obtainable

a boxer (participant in a boxing match) / a boxer (breed of dog)

support, assistance / aftersales support

give support, assist / provide aftersales support

briefs (male underwear)

balance (condition of a system in which competing influences are balanced)

to be balanced

(と〜) thinking that […] (with the next clause explaining that the truth is contrary to expectations)