An element of clear up (like the sky clearing up!) is so wonderful and splendid. Sort of a weird word, but very useful. Just think of that wonderful feeling you get when the sun breaks and things clear up and it's awesome.
The reading is a bit weird, too. Luckily, you've learned both of them already. 晴れる is はれる. That's the reading you use here, though は goes to ば.
"Don’t sell yourself short like that. You’re a magnificent woman."