To have the potential of ever being happy in this way necessarily requires a good character (ēthikē aretē), often translated as moral or ethical virtue or excellence.
tə hæv ðə pətˈɛnʃəl ʌv ˈɛvɚ bˌiːɪŋ hˈæpi ɪn ðɪs wˈeɪ nˌɛsɪsˈɛɹᵻli ɹᵻkwˈaɪɚz ɐ ɡˈʊd kˈæɹɪktɚ ˈiːθaɪk ˈæɹiːt, ˈɔfən tɹænslˈeɪɾᵻd æz mˈɔːɹəl ɔːɹ ˈɛθɪkəl vˈɜːtʃuː ɔːɹ ˈɛksələns.