、。
She couldn't see it, but she did feel it.
Literal
She [topic-は] that [object-を] see [thing-こと topic-は] cannot-do [but-が], that [object-を] feel [topic-は] did.
Two contrastive uses of は frame the symmetry. 見ることはできない uses the potential pattern ~ことはできない — 'cannot do (the act of) seeing' — with は marking 'seeing' as the contrasted topic. The second clause, 感じはしました, splits the verb 感じる ('feel') into stem 感じ + は + する, the focus-marking pattern [verb-stem]+は+する meaning 'do indeed (verb), as opposed to other actions.' Together: 'couldn't see it, but did feel it.' The pattern stem-は-する is a slightly literary way to emphasize that an action did happen, often used in contrast.