﴿ وَإِذَا جَآءُوكُمْ قَالُوٓا۟ ءَامَنَّا وَقَد دَّخَلُوا۟ بِٱلْكُفْرِ وَهُمْ قَدْ خَرَجُوا۟ بِهِۦ ۚ وَٱللَّهُ أَعْلَمُ بِمَا كَانُوا۟ يَكْتُمُونَ ﴾

“For, when they come unto you, they say, "We do believe": whereas, in fact, they come with the resolve to deny the truth, and depart in the same state. But God is fully aware of all that they would conceal.”

Please check ayah 5:63 for complete tafsir.