promisor       
noun [ C ]  law specialized uk/ˈprɒm.ɪs.ər/ us/ˈprɑː.mɪs.ɚ/
 立约人,要约人,承诺人
a person or group that has made a promise
  Would the promise of a complete stranger to pay a mother to maintain her child be binding on the promisor?  一个完全陌生的人向一位母亲支付抚养孩子的费用的承诺对承诺人有约束力吗? 
 Compare: promisee
 - More examples
 - The person making the promise to pay is also known as the promisor.
 - In his opinion the promise involved the promisor in two possible actions for breach of contract.
 - In this case the promisor made it clear that she did not intend to be legally bound.
 - Promises that are only to be carried out at the promisor's discretion cannot create a binding contract.