Mable P.O.V
He kissed me?! On the lips?!! Why....I pushed away from sans and looked down.
"Mable?" He said. I looked away and thinking or horrible things I've done. After that I cried each time.
"I-I'm so s-s-sorry!!!!!!!" I cried out. I laid against him with my hands on my eyes while crying. Sans looked at me and said nothing. I took a peak at him and he was in tears too, but smiling. I looked down again and kept crying. Good thing the walls were sound proof for papyrus and frisk to hear, but they can't. I cried and cried and cried softly until sans hugged me. I gasped and looked at him. He saw my tears were running down to my cheeks.

Sans P.O.V
I smiled for a while when Mable was in tears. I felt her pain so I told her a joke
"Let me tell you a joke Mable: Knock knock".
"Hehe, who's there?" She chuckled as she wipe her tears away
"Stop".
"Stop who?". Then I put my hand on her cheek and said
"Stop crying and smile for me". Mable touched my hand and laughed. Then she put a kind, warm smile for me
"Haha that's not a joke!" She laughed. I've moved my hand and I walked to her dresser and grabbed the family photo that everyone was in. Mable was in the middle, me, frisk, and papyrus was right next to her. Then I felt Mable's heart was turning white but it was gray. I smiled and turned around and said
"Mable can I ask you something"
"Well sure". She said
"Are you getting nightmares everyday?" I asked
"Yea.....I'm tired getting alone, it's cold here too.". I took a breath but my heart was beating fast and I started to blush
"Well....umm....uhh...can I..sleep with you......tonight". I stammered. Mable blushed and I looked down
"Sans...." She whispered. She walked up to me and hugged me. And she said sure. I hugged back
"I love you sans, and I promise...we will save this world...together....."