Certain actions in this game require some kind of consent in order to be performed. For instance, you wouldn't want just anyone taking off your clothes, or feeding you some unknown drug.
Consent is given with the 'trust' system. You may trust people to perform individual actions, or put complete trust in them, allowing them to do EVERY trustable thing to you.
help @trust, for info on trusting/untrusting folk.
help @trusted, for info on how to list who you trust.
help trustable actions for a complete list of actions which require trust and their descriptions.