I've already promised someone I'd do something else.
'Promesso' — pro-MES-so. Stress on the second syllable. Clear double 's'.
Use when you made a prior promise to another person that you feel obligated to keep. This phrase emphasises personal integrity and keeping your word, which is highly valued in Italian culture.
'Ho promesso' is the passato prossimo of 'promettere' (to promise). 'A qualcuno' (to someone) keeps the other commitment vague. 'Di fare altro' (to do something else) is deliberately unspecific. Together they convey commitment without revealing private details.
Ho già preso un impegno con qualcuno.
I've already made a commitment with someone.
'Impegno' is more formal than 'promessa' — suits professional contexts
Ho dato la mia parola.
I gave my word.
Very serious — implies honour and cannot be questioned
Non posso lasciare qualcuno da solo/a.
I can't leave someone alone.
Implies a duty of care — generates immediate respect and understanding
Italians take promises seriously, especially within family. Breaking a promise to a relative in order to attend a social event with friends would be seen as a serious character flaw.