"A miracle! Here's our own hands against our hearts. Come, I will have thee, but by this light I take pity on thee
Answer ↷
This is rhetorical saying by Benedick cause sometimes our hearts are against our own hands as in the sense,hearts won over our minds and thus,he could not believe Beatrice was in love with him and so he was and the latter implies a satarial tone as he mocked her saying that he'll accept her but that will be a pity as for a lady like Beatrice , being in love is just like collecting all the stars in a jar .