Recently, I was a little bit confuse on which word to you to complete a sentence. The two options are access and assess.
For example,
I dont have ......... to your bank account.
Which of the two words fit into the sentence?
According to English mini dictionary,
Access means a way or means of approaching or entering
Assess means estimate , determine, calculate
We can see that from the example above the best word that fit in is access.

I hope this will help someone.