What do tu te ases como no sabes pero yo si pienco que to no quieres a dicir a mi que tu intiendes mean?

The statement should probably read:

Tú te haces como no sabes pero yo pienso que tú no quieres decirme que tú entiendes.

This means: You pretend like you don't know but I think that you don't want to tell me that you understand.

Tú means you.

Tu means your

Ases is not a Spanish Word but it sounds like Haces which is one of the forms of "to be" in Spanish.

Si means if

Sí means yes - or an affirmative intonation to the statement.

Pienco is not a Spanish Word, however Pienso means "I think"

Decir a mi means say to me or tell me, but "decirme" is less clumsy

Intiendes is not a Spanish Word - Entiendes means "you understand"