Ossan Boukensha Kane no Zenkou

Meet Kane: a D-rank adventurer with nothing going for him but his kindness. He's spent the last 20 years getting by with herb-picking requests, but one day, he comes across a super rare item: The Fruit of Revival! Giving it away for not much more than pocket change, little does he know that his life is about to change...

(Source: MANGA UP!)