Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dulcesco, dulcui, 3, v. inch. n. [id.], to become sweet, Cic. de Sen. 15, 53; Plin. 3, 18, 22, § 127; 31, 7, 41, § 70; Paul. Nol. Carm. 17, 23.