The phrase "pulled one's leg" refers to a form of teasing or joking. It's a common idiom in colloquial English, and its antonyms would be serious, sincere, trustworthy, and genuine. In other words, when someone "pulls your leg," they're making light of something or not being honest with you. If they're serious, they're not joking and aren't trying to trick you. Sincerity and trustworthiness are the opposite of being pulled someone's leg. It's important to understand these antonyms to avoid misunderstandings and to communicate effectively with others.