Expressing sincere apologies is important in any language. While "I'm really sorry" is a direct translation of "Saya betul betul minta maaf", there are other ways to convey the same sentiment in English. You could also say "I am truly sorry", "I deeply apologize", or "I am extremely sorry" to emphasize the sincerity of your apology. The best phrase to use depends on the situation and the person you are apologizing to.