。
She put the house up for sale.
Literal
She [topic-は] house [object-を] sell [purpose-に] put-out.
売りに出す is the standard set phrase for 'put up for sale, offer on the market.' It uses the productive V-stem + に + V-of-motion pattern, where the V-stem (売り, from 売る 'sell') marks purpose and the second verb (出す, 'put out') is the action. Same shape as 探しに行く ('go searching') or 助けに来る ('come to help'). The に here marks purpose, not destination — a useful pattern to internalize.