Which apostle wrote the letter that says 'Love is patient, love is kind'?

Answer: Paul

1 Corinthians opens with "Paul, called to be an apostle of Christ Jesus," and chapter 13 describes love.

“Paul, called to be an apostle of Christ Jesus by the will of God, and our brother Sosthenes, Love is patient, love is kind. It does not envy, it does not boast, it is not proud.”— 1 Corinthians 1:1, 13:4 (BSB)