Was thinking about this some more ... entretener is another, although there's also divertir for entertain.
Pertain could be pertenecer, but it doesn't quite follow the pattern. There is no pertener.
Attain has a false friend atener. Not the same meaning. http://www.spanishdict.com/translate/atener
In what context does this sentence work?
Does it just mean "I can keep it going/maintain it/keep it up", or does it also mean "I can get behind/go along with that" as well?
The English translation seems to imply the latter more than the former to me, but the similarity to English "maintain" tends to make me think it might only mean the former.