User blog comment:FairyRaven/Fairy Tail Chapter 425: Sabertooth X792, Review and Commentary/@comment-5303512-20150323141838/@comment-7418318-20150323174551

I'm with B214 on the matter. To me this looked like she was sad that he wouldn't trust her enough to just tell her whatever it was that bothered him.

It also makes sense. First he disappears on her for a year, then he ripps her out of the life she just established without asking her and now he demands that she trust her, without bothering to tell her anything.

On one hand I can understand why Natsu is rushing so much that he can't put any thought into how to tell her and why we won't just blurt it out, but I can also understand why Lucy would be hurt or disappointed by his behaviour... at least until he finally give an explanation.