Her ability to be merry in the face of difficulties is one of her very many admirable qualities. He will tell this to anyone who will listen.

'It would perhaps be possible for you to meet your mother. If you would like to.'

He could simply lead her over to Fantine's table. But that might be a cruel shock; better to give her the choice, in case she needs to build her courage.

Of course, as he says it he realises that he has never spoken of his relationship with Fantine to her. A cold hand grips his heart - but there, it is done, and now must be borne. He should have considered more carefully perhaps; except no, it does not matter. He would not keep the two apart for any reason.