After about a month, Chara still isn't ready to talk to Y/n about how she feels. But that doesn't stop her from trying to spend time with him. 

Chara joins Y/n on a shopping trip. 

Y/n and Chara get what they need and head home. They find themselves alone, there was no better chance for Chara then now. 

Chara: Y/n. C...can we talk?

Y/n: Of course.

Chara got more nervous.

Chara: I...I've wanted to tell you something for a really long time.  At first, it was just me being a stupid kid. But it never changed.   I don't want to be a kid to you, I want to be a woman in you're eyes. I...love you.

Y/n stood there for a second and didn't say a word.

Y/n puts his hand on Chara's head.

Y/n: Chara. You are very brave. 

Chara pouts.

Chara: I just told you to stop seeing me as a child! I'm over a hundred years old!

Y/n chuckles.

Y/n: I know.

Chara: Well...what do you think? Will you be mine?

Y/n didn't respond, instead he picked her up and laid on the couch and placed her on top of him.

Y/n: This answer you're question?

Chara blushes and lays down on his chest.  It's something she wanted to do for so long.

Y/n began to doze off. When he fell asleep, Chara gave him a kiss on the chin.

Chara laid there until she fell asleep as well.

Toriel was the first to come in. She walked in the door and saw the two sleeping.

Toriel in head: I see that it went well for you, my child.  I do hope that you two won't nap for too long, or else you won't sleep the whole night. 

A few hours later, Chara woke up. She yawned and sat up, Y/n didn't seem to even notice her weight shifting on top of him. 

Chara gave him a kiss on the forehead and got off of him.  

Chara walked into the kitchen and saw Toriel.

Chara: Hi mom.

Toriel: I see that you talked to Y/n.

Chara: Yeah.

Toriel: I had to talk to you're father about it. I reminded him that you're older than every human alive right now. You can chose who you want to be with. 

Chara: Mom. Did you and dad know Y/n when you were kids?

Toriel: What an odd question. Where did that come from? 

Chara: I remember that you and Y/n would talk a lot about "the old days" when I was a kid.  

Toriel: You were half right. You're father was the prince of monsters. I knew Y/n since we were little monsters, running around and playing.  You're father was so nervous when he first met me.   Y/n eased the tension in the air so often, I think he's the reason that Asgore even stumbled a sentence out.

Chara chuckled.

Toriel: Sure, it's weird to think about because of what you want to be to him. But on the other hand, I suppose there is no safer bet for me to entrust you're future to. My father was hesitant on Asgore because of the royal bloodline.  Asgore's father wasn't as kind of a ruler as he is. 

Chara: That would explain why he doesn't talk about him.

Toriel sighs.

Toriel: Yes.

Chara: What was Y/n like back then?

Toriel: He didn't change much. He got more serious around the time he became a royal guardsmen.  He trained for a long time and was naturally gifted.  But during the war, his family was killed and so was all the Oni's. Y/n is the last Oni left.   

Chara's stomach starts to growl.

Toriel: It is almost time for dinner, do me a favor and wake Y/n up.

Chara nods and goes to Y/n. She shakes him gently and Y/n wakes up.

Chara: It's time to get up, dinner will be ready soon.

Y/n sits up.

Y/n: Did you have a nice nap?

Chara blushes.

Chara: Yeah. I wanted to do that for so long. 

Y/n: Well, guess we should get ourselves ready before Toriel yells at us for it.

Chara chuckles and the two get prepared for dinner.

That same night. Y/n was looking at the flowers.

Y/n: Asgore did a good job with these.

Asgore: Indeed I did.

Y/n turns and Asgore stands next to him.

Asgore: I remember when I had a garden ten times this size.

Y/n: And it took you ten times longer to manage.

Asgore: I had time back then. Not so much now.

Y/n: Yeah.

Asgore: Y/n. I never apologized for the way I treated you, all those years ago. You were right.

Y/n: Don't worry about it, in the end it all worked out.

Asgore: And I also know about my daughter.

Y/n: Asgore.

Asgore: Toriel already talked to me about it. *sigh* She's her own woman now. She might not look like it, but she's old enough to make her own decisions.

Y/n doesn't say a word.

Y/n: I probably should head to bed. Frisk has a diplomatic meeting with the Japanese ambassador we have to catch a flight for. Frisk was already planning on taking Chara as a plus one.

Asgore: Are you sure you want to go there?

Y/n: It doesn't matter. Frisk needs to go there. And I can't refuse to do my duties for something that happened centuries ago.