No. SMS are very difficult to prove. Say you will take print out of sms mentioning that she/he sent on so and so time and date.
Questions:
what is the gaurantee that it was sent to you on said so and so date and time?
In such case anyone can tell/create that it was sent. SMS though genuine, put on plain paper can never be proved. It is common sense. Even messages on phone can be proved false easily, as these days, it is easy to modify the messages with the help of any editors.
Only genuine message (correct in number and content) obtained from service provider upon notice from court and approved by forensic will hold good and easy to prove. Rest all cases, it is difficult to prove and get challenged easily by opposite party.
FYI, I contacted some detective agenices for extracting the smses with contents some time back. They didnot get me the contents of smses even for a day old messages.