This line is ironic because the writer

"i do not, therefore, so much as hint to you how absolutely dependent you are upon me; that you neither have nor can have a shilling in the world but from me; and that, as i have no womanish weakness for your person, your merit must and will be the only measure of my kindness."

a. emphatically mentions his great wealth and his unwillingness to share it with anyone
b. is actually dependent upon the recipient's generosity for his own personal welfare
c. claims he will not allude to the recipient's dependence on him while actually emphasizing it
d. claims that only a woman with weakness could love the recipient and that he is not a woman
e. reveals that he will no longer support the recipient monetarily because the writer is excessively kind