韓劇《49天》的主題曲名為《以為只會忘記》，由徐英恩演唱。這首歌曲的時長為4分11秒，收錄在《49 Days OST》專輯中。以下是韓文歌詞的一部分：1. ?? ??? ?? ????? ??? ??? ??? ??? ?????? ??? ? ???2. ????? ?? ? ?? ??? ??? ?? ? ???? ??? ?? ?? ???? ?3. ?? ?? ?? ?? ????? ?? ?? ???? ?? ??? ???4. ?? ??? ?? ????? ??? ? ??? ??..5. ?? ??? ??? ??????? ?? ?? ???? ???? ?? ????? ??? ????6. ?? ?? ?? ? ???? ?? ?? ?? ? ??? ???? ?? ??????? ?? ??7. ?? ??? ??????forgetting the lyrics, but here's a portion translated into English:1. My throat is blocked, I can't speak,staring at the sky blankly,I cry and try to forget,please, let me forget.Alone, I tell myself to stop,my heart aches, it's all on fire.They say love doesn't exist for me,they say.2. I promise to stop, to just stop,I'm all alone, I tell myself,no more, that's enough.My heart is so heavy, it's all confusion,love and such, I have no part.3. Please, just forget, I plead,I promise, but your image keeps returning,it circles back to my heart.4. It's just an ordinary day,if I forget about me for a while,it might be alright...5. Crying, then laughing, then falling asleep,picking up the phone, hanging up again,I'm such a fool, why do I keep doing this?6. I want to see you, I'm going mad,I want to forget, I'm going mad,I'm so tired, too tired,tears block my sight.7. Your figure seems blurred,now, even when I try to forget,it feels like it's time to let go,why am I still struggling?Why can't I just forget,and why can't I make myself turn back?I'm...Please note that the lyrics provided are not a complete translation and may not be entirely accurate. The context of the song and the emotions it conveys are important to the understanding of the drama's themes and the characters' experiences.