Ona - to (when used w. verb, eg, ua mafai ona pese (able to sing). Ona - so, then (when used with 'lea'), ona pau lea - that is all. 'Ona - because, on account of. Ona (o-nah) - drunk, poisonous, septic, infected.
E mafai ona ta uo?
E mafai ona ou mauaina lau numela?
E le mafai ona ou faatali.
Ua le mafai ona ou manava
If you mean "oga or ona", then it's drunk (he was drunk - ua ona ia). Oga or ona can also mean, poisoned by something eaten (food poisoning). (Na ona i le i'a na ia aia - she got food poisoning from the fish she ate).
E mafai ona ou a'oina oe i se aso
E te iloa e fa'apefea ona ou fiafia iai.
O a'u e ona, o la'u mea, o le mea a a'u
O a'u e ona, o la'u mea, o le mea a a'u
Alsowe is not a Samoan word.
E le mafai ona ou ola e aunoa ma oe.
E tatau ona e tautala/talanoa - if you're saying to someone that they need to speak/talk. E tatau ona lua talanoa - if you're advising someone that s/he needs to have a talk with someone else.