How to calculate the similarity between two sentences in Rasa?

how to calculate the similarity between two sentences in Rasa?I want to use the components or use the inner way of Rasa to calculate the similarity ? Is there some codes or config?

For example: sentence1: “I eat breakfast”

sentence2: “I eat now”

sentence3: “I eat breakfast after 10 minutes”

They are one intent.

now I have a sentence0: “I will eat later” ,

now I only can use the other library files of python.such as the: import macropodus; import Levenshtein. but the effect is ordinary,the similarity is about 0.5~0.7 how about the way or components of Rasa? I want make its’ confidence is about 0.9 above. How to do it? how to compare the sentence0 to one intent?

I need help.Thanks

or input one sentence, how to know it isn’t the designative intent?such as input the sentence0: “I will see movie” , the original intent is “eat”.

intent: eat

sentence1: “I eat breakfast”

sentence2: “I eat now”

sentence3: “I eat breakfast after 10 minutes”

how to calcucalte it, is there some detailed code?