It is important to keep in mind that all Yantras are a form of instruments carrying the potential of enhancing one's life. Although, these Yantras are designed to attract favourable outcome, they don't force anything to happen that is against the natural Karma. Outcomes from the Yantras mainly depends on the mentioned factors and right type of mantra chants. For instance, if the situation is not meant to be, the you will not be able to force someone to love you. This would be against the law of nature.
Everything happens in its own course of time, synchronizing well with the universe. Sometimes, what we wish for may not happen as per your wish. However, you, by heart connect with god and goddess for their blessing, things will change and the outcome will be positive. Like parents look into their children, god and goddess look over their earthly children and love them.
When things are meant to happen for us, with the right worship of Yantras and the respective deities will speed up the progress.