。
She's wearing a sweet-smelling perfume.
Literal
She [topic-は] sweet scent [attributive-の] perfume [object-を] is-wearing.
The verb for wearing perfume is つける ('attach / put on'), not 着る ('wear,' for clothing) — Japanese splits 'wear' across multiple verbs depending on what's worn and how (着る for clothing, 履く for shoes/pants, かぶる for hats, つける for accessories and applied items like perfume). 香水をつけている describes the resulting state — the perfume is on. 甘い香り ('sweet scent') uses 甘い in a sensory-mapped sense: 甘い covers literal sweetness and extends to 'sweet' smells, 'sweet' voices, even 'sweet' (= naive/lenient) attitudes. This synaesthetic stretch happens in many languages, but Japanese leans on it heavily.