Potty training can be sressful for both parent and child alike. Most suggestions are based on speaking calm and relaxed. If it feels like it isn't working you need to be more patient, its not a race.
Speak softly and assure them it is alright. Potty training takes time and if it isn't working it might not be the right time.
Use your words like you have been.
If he's ready, he'll go. If he isn't ready, he won't. I thought my son would never potty train. Never. He insisted that his pull ups weren't diapers, he refused to wear diapers because those were for babies (he has a new little sister) and I was desperate to only have one in diapers. He was 3.5 and just not quite ready. We started doing underwear only when we were all at home for the day, and he peed himself a few times and really didn't like it, and then one day he was just like "okay, i have to go potty." and he went. we ran out of pull ups for night time and had to put him in underwear, and he's been dry at night for a few months now, almost as long as he's been potty trained. he'll be 4 in february and i'd say he's been completely potty trained since october or so.
he's used to pull ups, so just keep encouraging him to go potty in the potty, read him potty books and get him excited about going potty like a big boy.