What does Mr. Laurence offer to the girls to go about ‘mending matters’?

Mr. Lawrence talks about music and famous singers:

he set about mending matters. During one of the brief calls he made, he artfully led the conversation to music, and talked away about great singers whom he had seen, fine organs he had heard, and told such charming anecdotes that Beth found it impossible to stay in her distant corner, but crept nearer and nearer, as if fascinated. At the back of his chair she stopped and stood listening, with her great eyes wide open and her cheeks red with excitement of this unusual performance. Taking no more notice of her than if she had been a fly, Mr. Laurence talked on about Laurie's lessons and teachers. And presently, as if the idea had just occurred to him, he said to Mrs. March...