A slightly critical observation in a feminine refined register. 察しがいい ('perceptive, quick to catch on') is a fixed idiom — 察し being the noun of 察する ('to sense, to perceive'). 心の機微 ('the subtleties of the heart') is a literary phrase used in the nuanced sense of emotional subtlety. 出来るように努力する ('to try to be able to do') is a fixed pattern for self-improvement. The sentence ends with the feminine reflective ~ないかしら ('isn't it the case...?'), a soft way to make a critical observation. Two topics (は...は) nested give Ren and 察し their own scopes.