There are a lot of factors to be considered
1. Love
2. Attraction
3. Commitment
4. Open-minded
5. Freedom
6. Sincerity
7. Attention
8. Connection
Most relationship starts with love at first sight and others started after spending time with themselves. Whichever one it might be, to find a life partner. There have a be a connection linking both partners, something called attraction. Sometimes you might be pulling away but there is this attraction which draws you both back, is like a magnet. Then you call is love but love is not enough reason for you to find a life partner, there are other requirements which needs to be passed to find a sincere life partner. The person will be attracted to you and all his/her attention drawn to you and will take every little opportunity or free time he/she has to call and check up on the other partner to know how they are doing. Being committed is another one, this shows that this isn't a mere dating but a serious relationship and we both partners need to put things together, sincerity can only comes in when both partners are open-minded and hid nothing from each other. No relationship is perfect but when there is trust, there will always be freedom to correct wrongs and open room for correction.
Finally, to find a perfect life partner, you need to be true to yourself and accept blames when one is wrong and take correction. Work on each other weakness and build something strong. When you find that person who appreciates you and always ready to stand with you even in downtimes then you know you have found the right partner..