In julius Caesar what does Brutus mean when he says this?

He's telling Portia to go inside and that he will be there shortly to comfort and embrace her and tell her of his heartfelt love for her. 'All my engagements I will construe to thee' means that whatever he fights for, he is doing out of love for her. 'All the charactery of my sad brows' means he will also state that his sadness is due to her self-injury.