Blue - word choice
Purple - grammar
Green - sentence structure
Do you believe in relationships?
In my opinion, humans are social by nature <s>whereby</s> (whereby is defined as by, through, or in accordance with which, it sounds odd in this sentence) <s>our day to day life is full of engagements</s> (Make live plural= lives/ agree the verb with the plural = are full of) (Better to split the sentence "humans are social by nature. Our day to day lives..). These engagements <s>could be presented in different shapes</s> <s>and forms</s> (means the same thing) (Maybe say - engagements can take different shapes):<s> it could be</s> with family to a stranger (maybe add "for example at the end. "it" can't be used since, has to agree with plural of engagement). All these are <s>a </s>relationships (plural, it you use "all these" you can't use "a" since "a" is used for singular). To take it to the next level, the bond that we have with God and animals, for some, <s>is</s> are also <s>a</s> relationships (make plural, since you said God and animals you have to make relations plural and make the verb agree with it).
Then, if all the engagements that we have or will make in the future are relationships then why do others label certain relations as a 'relationship'? The determining factor is the level of intimacy. Some <s>would be</s> are very close to the heart; some are distant, and the remaining are merely interactions. For example, think of the closest bond which is formed out of blood or marriage, family, or the buying and selling interaction at the grocery store with a <s>stranger </s>cashier. How do you <s>value the relationship</s> (Maybe say: "how do you determine the value of a relationship" - is you ask "how do you value" its more like you're asking how does one value ones own specific relationship and not a question on how to determine the value of different relationships)
It all boils down to human nature, <s>the nature</s> the drive to seek validation, support, and encouragement. In most cases, we tend to stick with a group of people that make us comfortable by providing these wants(?). Once we have found them, we <s>start to </s>value the interactions even amid challenges. That means humans are chasing after the person. We find ways to maintain the bonds with those people even when faced with the risk of separation.
Unfortunately, not all relationships last forever, but if we humble ourselves, communicate well, and <s>be</s> remain open for discussion, we can enjoy the fruits of any type of relationship as it is vital for existence.
To conclude, <s>a</s> relationships (use plural since you're talking about the general idea of relationships) <s>is</s> are <s>an</s> unavoidable and they are much needed for human life. However, instead of the relationship, we should always give our focus first on the person in the relationship.
I hope I have been helpful!