I believe the word you're looking for is "infinitely." Infinitesimally implies very small/not a lot: "1: taking on values arbitrarily close to but greater th

I believe the word you're looking for is "infinitely." Infinitesimally implies very small/not a lot: "1: taking on values arbitrarily close to but greater than zero 2: immeasurably or incalculably small <an infinitesimal difference>" (http://www.merriam-webster.com/dictionary/infinitesimal http://www.merriam-webster.com/dictionary/infinitesimal)