When Radhika's decide to become a Sevika, I think that was the best solution in those circumstances for her to become a Sevika. She gets rid of Ammaji and Devakiji, She gets rid of the society that keeps torturing her. She gets out of the way of Dev and Vish (her sister) life. She doesn't have to face Keshav's proposals. She doesn't have to agree for marriage again. She is already used to live the kind of life she is living at the ashram.
Wo afsana jise anjam tak lana na ho mumkeen
use ek khoobsoorat more dekar chhorna achha.
It will be quite tempting for her to go home with Dev.
But she should go only if she is willing to get in Dev's life and get rid of her obsession for Vish. She must realize that by rejecting Dev she is giving pain to him and forcing him to live with Vish is giving pain to Dev as well as Vish. So even if she doesn't want to reveal the truth she should not force Dev to accept Vish.
It's now or never.
She should go only if she wants to take care of herself too. If she goes back only to come back again for Vish would prove her to be foolish and weak. She is old enough to understand this.
If she decides to go back,
1. She should take care of her father
2. Should not let Ammji, Devaki or society bully her
3. Let Keshav know that he shouldn't expect anything from her
4. Live Dev alone if she doesn't want to be with him
5. She has paid back shastriji's family for all their ahsana's.
6. And let destiny decide the future.
And for Dev,
If Radhika doesn't come in his life; he should leave Vish and move on with his duties.
O dene wale tu ne to koi Qasar na ki
Ab kisko kya mila ye muqaddar ki baat hai.