Is it awkward because Thalassa turned down his engagement.

I'm actually a bit confused about why Pierce would deny having feelings for Thalassa now. Maybe it's because the bandit threatened Thalassa during the fight scene, but Pierce had no problems admitting Thalassa caught his eye in the first chapter.

I suppose it's not unusual for couples to get engaged so early on. This is a fantasy world, after all.

Sometimes your verb and noun agreement is off, and your verb tense is sometimes a little awkward. (By the way, if you need me to explain anything with examples and whatnot, don't hesitate to ask. I'm being pretty vague, sorry)