The meaning of saying «There is no god but Allah» sincerely

We were told by Sa’d bin Abdullah, from Ya’qoub bin Yazid, from Muhammed bin Abi ‘Umayr, from Muhammed bin Hamran, from Abu Abdillah, peace be upon him, that he said: The one who says: «There is no god but Allah» sincerely, will enter Paradise, and his sincerity is that «There is no god but Allah» will constrain him from that which Allah, Exalted and Glorious is He, has forbidden.

We were told by Sa’d bin Abdullah, from Ahmad bin Muhammed bin Isa, and Hasan bin Ali al-Kufi, and Ibrahim bin Hashim, all of them, from Hussain bin Saif, from Sulayman bin Amru, from Muhajir bin Hasan, from Zaid bin Arqam, from the Prophet, Allah’s blessings be upon him and his Family, that he said: The one who says: «There is no god but Allah» sincerely, will enter Paradise, and his sincerity is that «There is no god but Allah» will constrain him from that which Allah, Exalted and Glorious is He, has forbidden.