"I swear!" is a literal English equivalent of the French phrase Je jure! The pronunciation of the present indicative in the first person singular will be "zhuh jyoor" in French.
"I prefer to..." in English is Je préfère... in French.
Je suis... in French is "I am..." in English.
"Can I ...?" in English is Puis-je ...? in French.
"(I) am" in English is (Je) suis in French.
You can say "je le jure" in French to mean "I swear."
Je travaille! in French is "I'm working!" in English.
Je suis qui? in French means "Who am I?" in English.
Je me lève in French means "I am getting up" in English.
Je le savais in French means "I knew it" in English.
Que ne suis-je? in French is "What am I not?" in English.
"I dance!" in English is Je danse! in French.
Qui je suis, moi? in French means "Who am I?" in English.