No, and treat any operator who implies otherwise with caution. Polar bears are wild animals ranging over enormous distances of sea ice, and no itinerary can put one in front of you on schedule. Sightings are common enough on Svalbard voyages that most people come back having seen bears, often at distance. Nobody can promise it, and we won't.
The distance thing is worth setting expectations on. A lot of sightings are a bear a long way off across the ice, watched through binoculars or a long lens, rather than the close encounter in the marketing photography. That's still remarkable, and it's not the same picture.
If polar bears are the entire reason you're going, tell us that up front. It changes which region and which time of year make sense, and it changes how we'd frame the risk to you before you commit.