Learn English – Difference between “recently” and “lately”

1. Suasive is an adjective that, in Linguistics (Grammar), "denotes a class of English verbs, for example, insist, whose meaning includes the notion of persuading and that take a subordinate clause whose verb may either be in the subjunctive or take a modal."

2. Persuasive is an adjective as well, that means being "good at persuading someone to do or believe something through reasoning or the use of temptation: an informative and persuasive speech." OR "She was very persuasive!"

The difference, then, is that while the former denotes a grammatical class for verbs, the second is adopted the way you already know, with people, situations, etc.

EDIT NOTE: In the OED it says that a speech can be "suasive" but considering the OALD and my dictionary didn't have it, I supposed it was an old use or it fell into disuse. So I checked the Ngram on google and it confirmed what Billare said and what I was thinking.

These two words have different meanings, not merely different connotations. Part of the question was about whom it would be preferable to spend time with, a selfish person or a self-centered person?

One could be self-centered yet not morally bereft of compassion and generosity. Similarly, a self-centered person might want to further his or her objectives, whether or not that meant behaving selfishly in any given situation.

@Adel's comment is similar to my perception. Specifically, that a selfish person has a strong bias toward not giving anything-- time, money, effort, energy, or other support to anyone other than him or herself. And that seems much more unpleasant than the alternative.

A self-centered person would be inclined toward selfish behavior, but not necessarily so. Being self-centered implies finding oneself more fascinating than anything else. But it doesn't necessarily cause such a person to behave in the stingy, venal way associated with selfishness.