Is the sister's rejection of a suitor a true reliance on God, and is her quoting of the hadith, "Look at her, for that is more likely to engender affection between the two of you," out of place? And are the initial feelings of distress and discomfort whisperings from Satan?

If a servant seeks guidance from their Lord through Istikhara and finds comfort and ease, they should proceed with the matter; otherwise, they should refrain. There is no harm in repeating Istikhara when in doubt. One should not rush to reject a suitor; rather, they can meet him again, as reliance on Allah does not negate taking means. The hadith indicates the permissibility for suitors to see each other. If a woman does not feel comfortable with the suitor after seeing him, this is a valid deduction. Initial comfort is not a condition, as feelings may change later. She should not rush to refuse him; instead, she should deliberate and repeat Istikhara and consultation, while not being forced to marry someone she does not desire.