Honest, maybe, but not transparent. "I've got a pretty busy day that day and am not sure I can make it" - transparent "I don't know if I'll be up to going

Honest, maybe, but not transparent. "I've got a pretty busy day that day and am not sure I can make it" - transparent "I don't know if I'll be up to going to that that day" - transparent. "Hey, maybe; if I find nothing better to do" - transparent. "50/50 chance I'll be there" - all the charm of the last of those, without the transparency.