Abdullah bin Abi Bakr bin Muhammad bin Amr bin Hazm (may Allah have mercy on him) says that at the end of the letter which the Messenger of Allah (peace and blessings be upon him) wrote to Amr bin Hazm (may Allah be pleased with him) when he sent him to Yemen, it states: "Whichever Jew or Christian accepts the religion of Islam with a sincere intention shall have the rights of the believers and shall bear the obligations that are upon the Muslims; and whoever remains upon Christianity or Judaism shall not be put to trial (over it). Upon every adult, male or female, free or slave, is one dinar or its equivalent in cloth. Whoever pays this has the protection of Allah and of His Messenger, and whoever withholds it is an enemy of Allah, His Messenger and the believers."
This is munqati' (broken), and it is not in the connected narration.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجزية / 18674