This is the 1167th most frequent Japanese word.
幸い
"幸い" means "happiness" or "luck."
幸い is used to express a desired or considered fortunate outcome.
彼がお役に立てたなら幸いです。
If he could be of help, that would be fortunate.
幸い is used to express hope or a wish for a favorable outcome.
この計画が成功すれば、幸いと存じます。
If this plan succeeds, I would regard it as fortunate.
幸い is used to express a favorable condition or circumstance.