Music can be a powerful way to express emotions and potentially help to mend a situation. One song that could convey your feelings and show that you care is "Make You Feel My Love" by Adele. This song expresses a deep sense of love and commitment, assuring your partner that you're there for her no matter what.
Remember, every relationship is unique, so choosing a song that holds personal significance or resonates with your partner's taste in music could be even more meaningful. The key is to communicate your sincerity and willingness to make things right through your song choice and delivery. However, if you're not a confident singer, simply playing the song and expressing your feelings verbally can be just as effective.