Not exactly 1)I didn't want to insult him by not staying for lunch. Gli non ho voluto insultare perchè non risto (stay or remain) per cena. . GRAMMAR: INSULTARE+OBJ Insultare+lui>insultare+lo>insultarlo Insultarlo or the obj before L'ho insultato. IN YOUR SENTENCE: Non l'ho voluto offendere non rimanendo a pranzo da lui. Insultare means saying very bad words to someone. Offendere means to make someone sad because you do something wrong or you say bad words. But insultare is worst than offendere. 2)I felt insulted by his remarks. Ho sentito insultare ........... Here the right translation is: mi sono sentito offeso dalle sue osservazioni. Probably he said you didn't cook well so you were offended by this comment, but not "insultato". Insultato could be in case: An angry lorry driver mi ha insultato by saying that I am a bitch. As you see the use is different.

=== In reply to your comment, Fran /che si fosse/ is the subjunctive mood, past tense, which is appropriate in this context that is expressing a possibility of a past event. Subjunctive mood is not an easy subjecvt, not even for Italian mother tongue speakers. It is needed under certain semantics like: a) possibility b) wish The story is quite long and (I think) should be addressed examining examples you would like to propose, one at a time.

Nel primo contesto in genere usiamo il verbo /offendere/ nella forma passiva. Non vorrei che si fosse offeso perche` non sono rimasta a cena. Mi sono sentita {offesa, insultata} {dai suoi commenti, dalle sue parole} ...

Hello Fran, I think in both cases it's better to use "offendere". Non volevo offenderlo non restando per cena. Mi sono sentita offesa dai suoi commenti. I think i would say " Ha insultato la mia intelligenza". he insulted my intelligence. Or the girl bad-mouths her boyfriend everywhere: la ragazza insulta il suo ragazzo ovunque.

yes to both questions. " Gli non ho voluto insultare perchè non risto (stay or remain) per cena.." this is best written as "non l'ho voluto insultare non restando per cena"