For this reason, anyhow, see Cuba (7)
I believe the answer is:
because
'for this reason' is the definition.
(because of this...)
'anyhow see cuba' is the wordplay.
'anyhow' indicates anagramming the letters.
'see'+'cuba'='seecuba'
'seecuba' anagrammed gives 'BECAUSE'.
(Other definitions for because that I've seen before include "Thanks to this" , "Beginning to explain" , "Owing to" , "On account of" , "Since" .)