What does まっすぐな瞳 bit mean in the following? Context: Person R is talking about person F, how they don't need to test F on their growth in power and such. Then this line is said: > R: F ―― > > R:F has a more straightforward gaze/look in their eyes than when they were with me…and F is simply brimming with mana. Also F tends/tended to being less confident in themselves I think R is trying to say that F is more self confident and such...

The first two words that came to my mind to describe this phrase was "pure" and "determined". Someone might suggest more fancy translation, but the basic meaning is simple. It's an antonym for a wicked and/or distracted look.