As Spyros's answer is both brief and easy to misunderstand, let me add a bit:
What you heard is "s' agapo", Greek for "I love you". Now here is an illuminating story if you speak French. The great French singer Edith Piaf was, towards the end of her life, married to a Greek called Theo (Theofanis) Lamboukas. She would probably tell him "I love you" in Greek quite often, for he became known as Theo Sarapo. Now if you can read French with the correct accent, you will know exactly how "s' agapo" is pronounced.