miri

Miri is intransitive and takes pri for the thing that amazes you, or a ke clause. It is not admiri, which is about approval rather than surprise, and it is not English wonder in the sense of idly asking yourself something - for that you want mi demandas min, ĉu. The causative gives mirigi, to astonish somebody, and -ind- gives mirinda, worth marvelling at. Mirinde and mire both work adverbially but mean different things: wonderfully versus in astonishment.