Is this real girls 🥲???

Do girls really mean when they say you are only person they would love and if it didn't work out they would be happily single ? After our breakup she got commited within one month . I couldn't believe my eyes . I know she is not like that and all but the boy she is newly committed is her school crush and I didnt know they were friends and all because I didn't even asked about him when I was in relationship because I thought she mainly messaged me and would ignore other boys in her dm for few days and then reply . I still couldn't believed how it happened within a month . I would be happy for her if that new guy is the right person for her but still how could she change so fast 😭. I cried miserably that day when I knew about her new bf . If it was after 1 yr it is understandable she would have probably moved on but this ?? Give me ur opinion