She might become angry at first. Natsu is known for her fiery temper. So, she could lash out at the person who betrayed her, confronting them directly and demanding an explanation.
He might initially be shocked and confused. Natsu has always been so loyal to Fairy Tail, so this would be a huge blow to him.
Natsu would likely be extremely hurt. He has always been loyal to Fairy Tail, so being betrayed would be a huge blow. He might initially be in disbelief, not wanting to accept that his friends and guildmates could turn on him.
At first, they might be in disbelief. The members of Fairy Tail see Natsu as a core part of the guild, so it would be hard for them to accept that he has betrayed them. They would probably try to talk to him and find out what's going on. Some members might be angry immediately, thinking that he has turned his back on their family. But others, like Lucy, might be more hesitant to believe it and would look for a way to resolve the situation without conflict.
Natsu might be initially shocked and confused. He's not the type to expect rejection, so he could be at a loss for words at first. For instance, he might just stand there with his mouth open, not believing what he just heard.
Well, in many fanfictions, Natsu might initially be in shock. He's a passionate character, so he could react with anger. He might lash out at Lisanna or the person she cheated with. He could also go into a state of self - doubt, wondering what he did wrong.
He might initially be in disbelief. Natsu is used to the loyalty among his Fairy Tail comrades, so betrayal would be a shock to him.
Well, Natsu is a passionate character. He could react with a lot of excitement. He might pick Lucy up and spin her around, laughing and saying how amazing this is. Or, he could also get a bit worried and start asking Lucy all sorts of questions about her health and what they need to do next.
Natsu would be heartbroken. Fairy Tail is like his family. He'd probably go on a solo journey to clear his name and prove his loyalty. Erza would be stoic but deeply hurt. She'd start an investigation within the guild, using her influence and intelligence to uncover the truth. She might also isolate herself a bit while she figures things out.
He might be initially shocked. Natsu is a character full of energy and sometimes a bit clueless. So he could be stunned into silence for a moment before breaking into a huge grin, excited about starting a family with Lucy.
Natsu would likely be extremely guilty. He might immediately stop whatever he was doing and rush to Lucy's side.