Technically for all competent cultivators it should be exceedingly easy to find a partner. I reckon it could be more of a challenge to find a partner who is highly talented. Such cultivators naturally would be mainly concerned about their own progress, so capturing their attention romantically would be a real trial, unless you have an extraordinary shared past with them. Arranged marriages also might not always be such a fruitful option because a sect or family wouldn't necessarily let go of a promising talent as it would weaken them. If it was within the same faction, that naturally wouldn't be a problem.