Explanation
Express the idea that 'it's not that it's impossible' or 'it's not that it cannot be done'.
Formation
Verb-ない form + ことはない
Detailed explanation
The ～ないことはない grammar point is used to express that something is not impossible, or not that it cannot be done. It creates a softer, more indirect way of saying that something is possible or can be done, but not necessarily easy or preferred.
Examples
Kono mondai wo tokenai koto wa nai ga, jikan ga kakari sou da.
It's not that I can't solve this problem, but it seems like it will take time.
Kare ni awanai koto wa nai kedo, amari hanashitakunai.
It's not that I can't meet him, but I don't really want to talk.
Kono eiga wo minai koto wa nai keredo, hoka no eiga ga motto omoshiroi to omou.
It's not that I cannot watch this movie, but I think other movies are more interesting.
Sono hon wo yomanai koto wa nai ga, nagai node ki wo tsukete kudasai.
It's not that I can't read that book, but it's long, so be careful.
Practice
Grammar content sourced from hanabira.org.