probable

cogent, compelling, conclusive, convincing, decisive, effective, forceful, persuasive, satisfying, strong, telling

acceptable, cogitable, conceivable, imaginable, possible, practical, reasonable

dependable, reliable, trustworthy

sophistic (or sophistical), specious

conceivable, earthly, imaginable, possible, potential, supposable

apt, bound, certain, doubtless, imminent, inescapable, inevitable, liable, necessary, sure, unavoidable