I find it helps when I filter the books I read by checking on what sort of authors wrote them ^^ - I trust various authors to lead me through the dark parts and still have a positive solution for the characters I care for. And by buying their books I try to ensure they have the opportunity to write more of that.

Non-grimdark authors for my money:

Sharon Lee
Sherwood Smith
Michelle Sagara West
Diane Duane (but of course)
Katharine Eliska Kimbriel
Robin McKinley
Martha Wells
P.C. Hodgell (although that is one series where the ending hasn't happened yet. Still the heroine keeps surviving with humour and determination and a way of creating bonds with others, which is amazing considering the role she has to play in the destiny of her people)

~ there probably are male ones, as well, but I have found with increasing age I prefer well written woman characters or protagonists, and I find that more often in books by women.