Daresay is appropriately flowery, but it is in fact just one word, not two. I daresay you need to use your own app more :p

The pot calling the kettle black, methinks.

http://flowery.app/words/I%20dare%20say

Dictionaries accept both forms, but the two-word phrase predates “daresay,” originating in the 14th century according to the OED.