What is the English meaning of 'Liber tuus et lectus est et legitur a me cum diligentia. Vis autem verborum intellegi non potest'?

The English translation of the Latin sentence 'Liber tuus et lectus est et legitur a me cum diligentia' is the following: Your book both has been read, and is being read, by me with care. The Word-by-Word translation is as follows: 'liber' means 'book'; 'tuus' means 'your'; 'et...et' means 'both...and'; 'lectus' means 'read'; 'est' means '[it] has been'; 'cum' means 'with'; and 'diligentia' means 'care'. The translation of the second sentence 'Vis autem verborum intellegi non potest' is the following: But the force of the Words can't be understood. The Word-by-Word translation is as follows: 'vis' means 'force, power, strength', even 'violence'; 'autem'* means 'but, however'; 'verborum' means 'of the Words'; 'intellegi' means 'be understood'; 'non' means 'not'; and 'potest' means '[it] can'. *The order is correct here. For the conjunction 'autem' is never to begin a sentence.