。
I really do get the feeling it's getting better, you know.
Literal
Truly well-becoming feeling [subject-が] do-[polite] [reason-もの].
Three layered constructions. よくなっている = よくなる ('become good / improve') + ている (state / ongoing) — the ている highlights the ongoing improvement. 感じがする ('to feel, to have the impression,' literally 'a feeling occurs') is the standard way to express 'it seems / I get the sense that.' The final もの is a softening reason-marker often heard in feminine speech, giving a justifying, almost pouting tone — 'because, you know.'