sinceramente betyder på engelska

in earnest▼(with considerable commitment, determination, or effect)
adverb
[UK: ɪn ˈɜː.nɪst] [US: ɪn ˈɝː.nəst]

sincerely▼(In a sincere or earnest manner; honestly)
adverb
[UK: sɪn.ˈsɪə.li] [US: ˌsɪn.ˈsɪr.li]I sincerely hope you'll get well soon. = Espero sinceramente que te mejores pronto.